A 27-car field, at least eight potential race winners and great battles for the pro-am1 and pro-am2 categories are the key prospects for the opening two races of the 2010 Porsche Carrera Cup GB, which bursts into life at Thruxton (3/4 April).There is much that is new about the Porsche Carrera Cup GB this season, but as the racing kicks off at the high-speed Hampshire track the old guard of Tim Harvey and Michael Caine should be at the forefront of the action.Eight drivers will make their Carrera Cup debut at Thruxton, as the championship heads into 2010 with a capacity list of 28 registered contenders. That's a fantastic response to the fastest one-make racing category in Britain and there will be fine competition across all three categories.In the pro category there is an intriguing mix of established Carrera Cup pacesetters and rapid newcomers. Harvey (Red Line Racing) and Caine (Motorbase Performance) need little introduction, but they face a raft of challengers including 2010 Carrera Cup GB Scholarship winners Michael Meadows (Red Line Racing) and Euan Hankey (Team Parker Racing). Both Scholars have impressive pedigrees, but neither has raced a Porsche at Thruxton before and will only have had limited running in testing ahead of Saturday's qualifying session.Then there is Stephen Jelley, also at Team Parker Racing, who has switched from the BTCC to the Carrera Cup for 2010. He's clearly a very accomplished racer with Thruxton experience from touring cars and British F3, while young Tom Bradshaw (JHR) is back for a second season after winning a 2009 Carrera Cup Scholarship. Lining up with Caine at Motorbase is Charles Bateman, back for a full season after only a couple of outings in 2009, but the biggest threat to Harvey and Caine may well come from Aberdeen teenager Glynn Geddie (Team Parker Racing). Geddie has won pro-am2 and pro-am1 titles over the last two seasons and is now more than ready to step up into the big time and challenge for race wins.That's eight contenders for the overall podium, but starting the season at Thruxton should favour the experience of Harvey and Caine. They know all about the unique challenge of Thruxton, where tyre management across a race distance can impact massively on the final result. Caine and Harvey were also first and second fastest in the pre-season test and media day at Silverstone last month.The pro-am1 category has a great line-up and two drivers stood clear of the pack at the close of the Silverstone test day. Ollie Jackson (Motorbase Performance) put down his marker for the pro-am1 season at Silverstone by setting fourth fastest time overall behind Caine, Harvey and Geddie. Jackson is leaner and fitter for the 2010 season and will surely be a major contender for the title. Meanwhile, Tony Gilham (ReDesign Racing) ran very strongly at Silverstone despite a distinct lack of other testing and should be the big rival to Jackson at this stage of the season.But there are plenty of other pro-am1 contenders, including single-seater converts Archie Hamilton and Oman-based Ahmad Al Harthy and racing returnee Andrew Shelley, who are all part of the six-car squad from Red Line Racing. Also in pro-am1 are the two Lithuanian drivers Jonas Gelzinis and Tautvydas Barstys from Juta Racing.In pro-am2, defending champion Glenn McMenamin (Red Line Racing) was top dog at Silverstone, but has never raced at Thruxton before. He has a gaggle of rivals including Mark Hazell (JHR), Paul Hogarth (IN2 Racing), George Richardson (Motorbase Performance) and George Brewster from Celtic Speed.Carrera Cup qualifying is on Saturday at 14.20, with the first race at 12.10 on Sunday and the second race at 16.25. The afternoon's racing will be shown live on ITV4 in the extensive BTCC race day programme.