Sonoma, California – Over 60 drivers across four of Pirelli World Challenge's seven classes are set to race at Sonoma Raceway, August 28 to 30 at the Grand Prix of Sonoma presented by KIA. With the 2015 season entering its penultimate weekend, GT/GTA drivers will compete in Rounds 18 and 19, while GT Cup drivers will run Rounds 16 and 17. Drivers in the GTS class will race Rounds 15 and 16.

The Pirelli World Challenge series makes its 17th appearance at Sonoma Raceway this weekend. The series first raced at the Northern California track in 1990. With 2015 being the inaugural season for GT Cup, this is the first time the class will compete at Sonoma.

Pirelli World Challenge GT: O'Connell and Beretta Vie for Supremacy in Drivers' Championship

With GT points leader Ryan Dalziel, of Windermere, Fla., missing the Sonoma weekend due to a scheduling conflict, defending 2014 champion Johnny O'Connell, of Flowery Branch, Ga., comes into the weekend looking to take over the lead – he currently sits second in GT Drivers' Championship points with 1477. O'Connell comes into the weekend carrying a ton of momentum having scored both wins at Miller Motorsports Park and will pilot the No. 3 Cadillac Racing Cadillac ATS-V.R. O'Connell's teammate, Andy Pilgrim, of Boca Raton, Fla., in the No. 8 Cadillac Racing Cadillac ATS-V.R, has had a hard luck 2015 season and sits 14th overall in GT.

After leading the GT Drivers' Championship for months, Olivier Beretta, of Monte Carlo, Monaco in the No. 61 Ferrari of Ontario/Toronto/Alberta Ferrari 458 GT3 Italia, comes into the Sonoma weekend third in points (1419) after two results out of the top 5 at Miller. Beretta has won three races this season and he makes his first PWC series start at Sonoma.

JD Davison, of St. Petersburg, Fla., in the No. 33 AE/Replay XD Nissan GT-R NISMO GT3 sits 4th overall in the GT Championship coming into Sonoma after scoring a pair of second place finishes at Miller. Davison makes his first career Pirelli World Challenge start at Sonoma – he has experience racing at the track in other series including an 18th place IndyCar Series finish back in 2013. Davison's teammate Bryan Heitkotter, of Fresno, Calif., will pilot the No. 05 Nissan GT Academy GT-R AE Replay XD Nissan GT-R GT3. Heitkotter was promoted to GT from GTA after finishing third overall in Round 15 at Mid-Ohio.

Kevin Estre, of Lochau, Austria, in the No. 9 K-PAX Racing with Flying Lizard Motorsports McLaren 650S GT3, enters the weekend 5th in the drivers' standings with 1124 points. After winning at Detroit, Estre looks to get back into victory circle as he makes his first career start at Sonoma. Teammate Robert Thorne, of Littleton, Colo. will pilot the No. 6 K-PAX Racing McLaren 650S GT3. Thorne finished second to his teammate Estre in Round 7 at Barber (Thorne's best result thus far of the season).

Bentley Team Dyson Racing heads into the weekend with Guy Smith, of Beverley, England, piloting the No. 20 Bentley/Breitling/Mobil 1 Bentley Continental GT3 and Chris Dyson, of Pleasant Valley, N.Y. behind the wheel of the No. 16 Bentley/Breitling/Mobil 1 Bentley Continental GT3. Smith replaces Butch Leitzinger in the seat of the No. 20 machine. Smith holds the PWC race lap track record at Sonoma. Dyson sits 6th in the championship and won at Road America.

Mike Skeen, of Charlotte, N.C., piloting the No. 2 DeVilbiss/Hawk Performance Audi R8 LMS ultra, enters the weekend 7th in the championship with 1051 points. Skeen looks to score his first win of the season at Sonoma. Last year Skeen won the Round 13 race at Sonoma.

Ryan Eversley, of Atlanta, Ga. in the No. 43 RealTime/Acura Motorsports/HPD Acura TLX-GT enters the weekend 8th in points. Eversley has one win on the season (St. Petersburg) and makes his first career Pirelli World Challenge start at Sonoma. Eversley's teammate Peter Cunningham, of Milwaukee, Wis. in the No. 42 RealTime/Acura Motorsports/HPD Acura TLX-GT holds almost every statistical series record and sits 11th in the championship.

Renger van der Zande of Nijmegen, The Netherlands replaces Dalziel behind the wheel of the No. 31 EFFORT Racing/World PMO Porsche 911 GT3 R. Michael Lewis, of Laguna Beach, Calif., was promoted from the GTA class to GT at Barber and sits 9th overall in the standings. He will drive the No. 41 EFFORT Racing/Curb-Agajanian Porsche 911 GT3 R.

The 17-driver GT field is rounded out by series veteran James Sofronas, of Pound Ridge, N.Y., in the No. 14 GMG Audi R8 LMS ultra GMG Racing/Spyder/Mobil 1, Duncan Ende, of Los Angeles, Calif. in the No. 64 Merchant Services Ltd./Linospresso USA Ferrari 458 Italia GT3, and Nicky Catsburg, of Kirchanschoring, Germany in the No. 25 Blancpain Racing Lamborghini Gallardo GT3 REX. Ende has experience at Sonoma having raced at the track in Pirelli World Challenge in 2014, while Sofronas has seven career PWC starts at Sonoma. Catsburg makes his first career start at the track.

Pirelli World Challenge GTA: Montecalvo Looks to Hold Off Challenges from Cisneros and Fuentes

Frankie Montecalvo, of Highlands, N.J. moved into the lead in the GTA Drivers' Championship with two wins at Miller Motorsports Park, scoring his fifth and six wins of the season. Montecalvo has been on a roll since Road America where he scored his second and third wins of the season in Rounds 12 and 13 and then at Mid-Ohio where he scored his fourth win in Round 14. Montecalvo will pilot the No. 66 Bayshore Racing DragonSpeed Mercedes-Benz SLS AMG GT3.

After leading the GTA Drivers' Championship for most of the season, Henrique Cisneros, of Miami, Fla. in the No. 30 MOMO NGT Motorsport Ferrari 458 Italia GT3 enters the Sonoma weekend in second. He enters the weekend with 1,587 points (106 points behind Montecalvo). Cisneros makes his first series start at Sonoma. Cisneros' brother Eduardo, of Miami, Fla. is also entered in GTA for Sonoma piloting the No. 29 MOMO NGT Motorsport Ferrari 458 GT3 Italia.

Martin Fuentes, of Mexico City, Mexico in the No. 07 Scuderia Corsa Ferrari 458 Italia GT3 comes into the weekend third in class points with 1,400. Fuentes won the Round 6 race at Barber.

Montecalvo's DragonSpeed teammate Eric Lux, of Buffalo, N.Y. will pilot the No. 08 Rembrandt Charms/Monticello Motor Club Mercedes-Benz SLS AMG GT3. Lux comes into the weekend fourth in class.

Turner Motorsport teammates Bill Ziegler, of Ponte Vedra, Fla., in the No. 95 Swisher Racing BMW E89 Z4 GT3 and Bret Curtis, of Austin, Texas, in the No. 32 Turner Motorsport/SPECTRA Resources Corp/United Steel Supply/Valspar Paint BMW E89 Z4 GT3 are entered in GTA. Curtis sits fifth while Ziegler sits eighth.

Drew Regitz, of Denver, Colo. will be in the No. 19 WWW.IRACERCOACHING.COM Audi R8 LMS ultra. Regitz sits 11th.

Rounding out the 12-car GTA field are Jorge De La Torre, of Mexico City, Mexico, in the No. 4 De La Torre Racing Motor LLC Aston Martin Vantage V12, Christina Nielsen, of Aarhus, Denmark, in the No. 7 Royal Purple/Orion Energy/LaSalle Solutions/PassTime USA TRG-AMR Aston Martin Vantage GT3, Henrik Hedman, of Ft. Lauderdale, Fla., in the No. 10 DragonSpeed Mercedes-Benz AMG SLS GT3 and Mike Hedlund, of Woodside, Calif., in the No. 65 Scuderia Corsa Ferrari 458 GT3 Italia.

Pirelli World Challenge GT Cup presented by MOMO: Can Thompson Continue His Dominance at Sonoma?

Colin Thompson, of Doylestown, Pa. continued his domination of the GT Cup class with his 11th win of the season in Round 15 at Miller Motorsports Park. Thompson will pilot the No. 11 Porsche of Bucks County/Penn Valley Constructors/Sherwin Williams Automotive Finishes/Austin Hatcher Foundation Kelly-Moss Motorsports Porsche 911 GT3 Cup. Thompson leads the class with 1901 points.

TruSpeed Autosport's Sloan Urry, sits second with 1329 points on the strength of five runner-up finishes, and four thirds on the season. He will pilot the No. 02 Security National/Engel & Volkers Porsche 911 GT3 Cup. Teammate Phil Fogg Jr., of Portland, Ore. will pilot the No. 18 Zoro/TruSpeed Autosport Porsche 911 GT3 Cup.

Lorenzo Trefethen, of Napa, Calif., heads into the weekend third in points with 1286. Trefethen scored his first career Pirelli World Challenge win at Canadian Tire Motorsport Park. He will drive the No. 13 Trefethen Family Vineyards Porsche 911 GT3 Cup.

Alec Udell, of The Woodlands, Texas will pilot the No. 17 Euroworld Motorsports/Amsource Capital/Panther Pipeline GMG Porsche 911 GT3 Cup. He scored his first career Pirelli World Challenge win in Round 12 at Mid-Ohio, and followed that up with a win in Round 14 at Miller Motorsports Park.

Preston Calvert, of Potomac, Md. in the No. 77 Phoenix Performance/Calvert Dynamics Porsche 911 GT3 Cup sits 5th in the championship – Calvert equaled his best result thus far with a 4th in Round 11 at Road America. Victor Gomez Jr., of San Juan, Puerto Rico in the No. 81 Porsche San Juan Porsche 911 GT3 Cup sits 7th in the drivers' championship.

Rounding out the field of eight GT Cup entries is Mitch Landry, of Lake Charles, La. in the No. 97 Landry Racing Porsche 911 GT3 Cup. Landry sits 6th in the GT Cup Drivers' Championship.

Pirelli World Challenge GTS: Five-Way Battle for Championship Continues at Sonoma

With a win in Round 14, Michael Cooper, of Syosset, N.Y., in the No. 10 Blackdog Speedshop Chevrolet Camaro Z28, vaulted into first place in the GTS Drivers' Championship with 1220 points. It was Cooper's third win of the season after winning at Circuit of the Americas in Round 2 and at Mid-Ohio Sports Car Course in Round 11. Cooper's teammate is series veteran Tony Gaples, of Libertyville, Ill., who will pilot the No. 11 Blackdog Speedshop Chevrolet Camaro Z28.

Andrew Aquilante, of Chester Springs, Pa., enters the Sonoma weekend second in the GTS Drivers' Championship with 1188 points. He will pilot the No. 32 Calvert Dynamics Phoenix American Motorsports Ford Mustang Boss 302. Aquilante's teammate Kurt Rezzetano, of Phoenixville, Pa., in the No. 37 Calvert Dynamics/Phoenix American Motorsports Ford Mustang Boss 302 comes into Sonoma third in GTS Drivers' points only 1186 behind Aquilante.

Dean Martin, of Westland, Mich., sits 13 points behind Rezzetano. He will pilot the No. 50 Rehagen Racing/Picture Cars East Ford Mustang Boss 302. Teaming with Martin will be 15-year-old Nathan Stacy from Owesso, Okla. who has moved up from TC to GTS fulltime, in the No. 14 Rehagen Racing Ford Mustang Boss 302.

Jack Baldwin, of Marietta, Ga., has clawed his way back into the championship and sits in 5th with 1140 points. Baldwin pilots the No. 73 GTSport Racing/Umphrey's McGee Porsche Cayman. Buz McCall, of Boca Raton, Fla. will again team with Baldwin as the pilot of the No. 72 GTSport Racing Porsche Cayman.

Also campaigning the iconic Chevrolet Camaro Z28 in the series is Best IT Racing's talented driver Andy Lee, of Colorado Springs, Colo., in the No. 20 Chevrolet Camaro Z28. Lee equaled his best result thus far of the season with a 5th in Round 13 at Miller.

Mark Wilkins, of Toronto, Ont., comes into the weekend 6th in points. He will pilot the No. 38 Kinetic Motorsports PutOnTheBrakes.Org Kia Optima. Partnered with him will be teammate Ben Clucas, of Northampton, England. Clucas pilots the No. 36 Kinetic Motorsports DonorsChoose.Org Kia Optima and comes into the weekend 7th in drivers' standings.

Jack Roush Jr. of Livonia, Mich. will pilot the No. 60 ROUSH Performance Capaldi Racing Ford Boss 302. Roush Jr. enters Sonoma 9th overall in the class drivers' standings.

Three-time series champion and winner of Round 9 at Road America, Lou Gigliotti, of Dallas, Texas will drive the No. 28 LG Motorsports Aston Martin Vantage GT4. Gigliotti sits 11th in class.

Series veteran Nick Esayian, of San Diego, CA, pilots the No. 34 Special Operations Warrior Foundation/Justap Stephen Cameron Racing Aston Martin Vantage GT4 after having been in a Ford Mustang Boss 302 to start the season. Esayian sits 12th in class.

Mark Klenin, of Lone Tree, Colo., returns to GTS with his own team. Klenin will pilot the No. 62 Schomp Auto/Invisible Glass/Premier Copier Klenin Performance Racing Aston Martin Vantage GT4.

Phoenix American Motorsports will also campaign the No. 35 Calvert Dynamics Phoenix American Motorsports Ford Mustang Boss 302 with Preston Calvert, Potomac, Md. behind the wheel. Calvert will do double duty over the weekend competing in both GT Cup and GTS.

Sonoma's TRG enters five cars for the weekend with Peter Ludwig, of New Paltz, N.Y. in the No. 13 TRG-AMR Aston Martin Vantage GT4, Jason Alexandridis, of Novato, CA, in the No. 75 TRG-AMR Aston Martin Vantage GT4, Derek DeBoer, of Ashland, Or., in the No. 09 BRM Chronographes/Racing for Cancer/Pirata Della Strada TRG-AMR Aston Martin Vantage GT4, Kris Wilson, of Monument, Colo., in the No. 07 TRG-AMR Royal Purple/Orion Energy/LaSalle Solutions/PassTime USA Aston Martin Vantage GT4, and Jeff Huber, of Menlo Park, Calif., in the No. 06 TRG-AMR Stand Up to Cancer/Exploratorium/Orion/Royal Purple/LaSalle/PassTime Aston Martin Vantage GT4.

Rounding out the 27-car GTS field is John Allen Denver, Colo. in the No. 16 ITEC/Bilt Racing Services/CVA/Isringhausen/CSFLN/JRZ/Joe Gibbs Driven/Canine Partners of the Rockies/Canine Hope for Diabetics Porsche Cayman, Nicolas Hammann, of Salt Lake City, UT, in the No. 23 Skullcandy Team Nissan Nissan 370Z Nissan GT Academy/Nissan/Nismo, Geoff Reeves, of Cleveland, OH, in the No. 40 Buffalo Trace Bourbon Shadow Works Racing Chevrolet Camaro, Kevin Marshall, of Incline Village, NV in the No. 44 VSA Motorsports Lotus Evora GT4, Paul Holton Talahassee, FL in the No. 78 AERO Advanced Paint Technology/Children's Tumor Foundation Compass360 Racing Audi TT-RS, and Jeff Harrison, of Grapevine, TX, in the No. 99 Gainsco/Bob Stallings Racing Hyundai Genesis Coupe.

Event/Circuit:
Sonoma Raceway, 11-turn road course (1.99 miles)

Qualifying:
Saturday, Aug. 29
· 10 a.m. GTS qualifying
· 12:30 p.m. GT, GTA, GT Cup qualifying

Race Lengths:
50 minutes (GT/GTA/GT Cup, GTS)

Live Internet Telecast (on www.world-challengeTV.com and www.motortrendondemand.com):

Saturday, Aug. 29
· 1:40 p.m. GTS Race 1
· 4:30 p.m. GT, GTA, GT Cup Race 2

Sunday, Aug. 30
· 8:40 a.m. GTS Race 2
· 10:40 a.m. GT, GTA, GT Cup Race 2

All times listed above Pacific

Television (on CBS Sports Network):
On CBS Sports Network Sunday, September 6, 5 PM: GT/GTA, GT Cup presented by MOMO. Wednesday, September 9, 9 p.m.: GTS. All times listed Eastern

Canadians In BOLD
Drivers On Canadian Teams In Italics