A total of 37 entries across the Pirelli GT4 America Sprint and SprintX series are set for action this weekend at Sonoma Raceway, which also sees the return of GT4 West competitors for the first time in more than two months.

It includes 21 GT4 Sprint competitors, led by TRG’s Spencer Pumpelly, who has retaken the points lead following his second win of the season last time out at Canadian Tire Motorsport Park.

Pumpelly holds a five-point margin over Team Panoz Racing’s Ian James, who claimed victory at the season-opening round at Circuit of The Americas, with newly minted McLaren factory driver Michael Cooper third in the standings.

Among the additions to the grid include the return Matthew Brabham in a CRP Racing Porsche Cayman GT4 Clubsport MR, which took part at Long Beach, along with the series debut for Erin Vogel in a Flying Lizard Motorsports Audi R8 LMS GT4.

Matt Fassnacht, who had been eying up a full-season Sprint run, is currently not on the entry list after finishing out of the points in both races at CTMP.

Hart, Travis Lead SprintX Command

Nolasport’s Jason Hart and Matt Travis, meanwhile, continue to hold a hefty lead in the GT4 SprintX Pro-Am standings in their Porsche 718 Cayman GT4 Clubsport.

It is one of 16 cars slated to do battle for the pair of 60-minute two-driver races that will also see several drivers and teams again pull double duty between both series over the weekend.

Nine of the entries will be competing for GT4 West honors, in its first race since its standalone round at WeatherTech Raceway Laguna Seca in March, in support of the California 8 Hours.

Track action kicks off on Thursday with testing, followed by practice sessions on Friday and the races slated for Saturday and Sunday.