***Thursday’s Pirelli World Challenge test sessions at Mazda Raceway Laguna Seca saw a number of incidents, resulting in two withdrawals due to accident damage, as well as two other cars needing extensive repairs to get back on track.

***The No. 82 McCann Racing Dodge Viper GT3-R has been withdrawn after an accident in the morning SprintX session. The multi-car accident also collected the No. 79 Alex Job Racing Porsche 911 GT3 R of Cooper MacNeil and the No. 7 No. 7 TRG-AMR Aston Martin Vantage GT4 of Craig Lyons. The Aston received extensive damage and is also done for the weekend but the team has pulled out a spare car.

***TRG team principal Kevin Buckler told Sportscar365 they hope to enter the spare No. 13 car for Lyons and co-driver Thomas Merrill in the SprintX races. The team expects to take parts from the wrecked No. 7 car, including the rear wing, to build up the No. 13 to full GT4 specification. It ran the afternoon test session without a rear wing.

***The other big incident came in the morning Sprint session, when the No. 3 Cadillac ATS-V.R of Johnny O’Connell had side-by-side contact with the No. 88 Bentley Team Absolute Bentley Continental GT3 of series debutant Fabian Hamprecht in Turn 9. The Bentley sustained left-front suspension damage.

***O’Connell returned to the track in the final half of the 40-minute Sprint test session following an extensive, nearly five-hour repair job from the Pratt & Miller squad rebuilding the right side of the Cadillac, in the middle of the paddock.

***21-year-old Hamprecht, a regular in the ADAC GT Masters with Team Abt, is filling in for Adderly Fong, who taking part in this weekend’s China GT Championship season finale in Shanghai with Absolute Racing.

***TRG is expected to field five Aston Martin GT4s in the SprintX races, marking the largest single-race effort for the team since the 2012 Rolex 24 at Daytona, when it ran five Porsche 911 GT3 Cup cars.

***The SprintX entry list has grown to 24 cars, nearly triple the number of entries that took part in the last round at Utah Motorsports Campus in August.

***Lone Star Racing has been a late addition, with its Dodge Viper GT3-R for Dan Knox and Mike Skeen. The team makes its first PWC start of the year after taking part in a four-race IMSA WeatherTech SportsCar Championship program.

***Stephen Cameron Racing’s Audi R8 LMS ultra has also been added to SprintX this weekend, with Drew Regitz and Kyle Marcelli at the wheel. Regitz will drive the same car in the GTA Sprint season finale on Sunday.

***GMG Racing’s brand-new Porsche Cayman GT4 Clubsport MR will also be pulling double duty, with team principal James Sofronas being joined by Matt Halliday in the SprintX races.

***The GT4 Clubsport MR makes it North American race debut after taking part in last month’s 24 Hours of Barcelona with Manthey Racing, as well as the recent GT4 European Championship round at the Hungaroring with three of the SRO GT4-homologated versions on the grid.

***GMG has shuffled its driver lineup, with Alec Udell set for his GT debut this weekend in the No. 14 Porsche 911 GT3 R alongside Brent Holden in SprintX. Uddell, who clinched the Sprint GT Cup title last time out at Sonoma Raceway, gives up the seat to car owner Chris Thompson this weekend.

***DIME Racing has withdrawn its Sprint GT class entry, which was originally listed for Jonathan Summerton. Team owner Rod Shegem told Sportscar365 they will instead focus on testing for 2017. The team was due to take delivery of a new Mercedes-AMG GT3 for this weekend but it’s understood to not have materialized.

***2015 GTA champion Frankie Montecalvo parted ways with the team prior to the Sonoma round, citing delivery issues for a promised replacement Mercedes-Benz SLS AMG GT3 chassis.

***John Edwards has replaced Kuno Wittmer at the wheel of the SprintX championship-leading No. 46 Mills Racing BMW Z4 GT3 due to Wittmer’s VLN commitments this weekend with the German manufacturer. The former IMSA GTLM champion has been taking part in series of VLN rounds to qualify himself for next year’s Nurburgring 24.

***Andy Pilgrim makes his return to the PWC paddock for the first time since being let go by Cadillac. Pilgrim teams up with Tim Pappas in the No. 54 Black Swan Racing Porsche in the SprintX races.

***While racing separate cars in the Sprint race, Gunnar Jeannette and Cooper MacNeil will team up in MacNeil’s No. 79 Porsche for the SprintX races. GTA (and SprintX) rules allow the Porsche 911 GT3 R a 2mm larger air restrictor compared to the car in the Pro class.