Two rounds of the Apex Tubulars Porsche Open Championship makes it a hectic Castle Combe Bank Holiday Monday raceday for some of the most dramatic and exciting cars in British Club Racing. The regulars head for the Wiltshire circuit after an exciting one-hour race at Brands Hatch which saw numerous lead changes and the action should be just as hot at Combe.The 997 GT3 Cup cars represent the latest racing Porsches, and three of these cars head the Class One entry driven by Nick Staveley, Tommy Dreelan and Andrew Tate. Staveley has already been a race winner this season, but Class One and overall opposition should come from the 996 of Mike Johnson. The Yorkshire man stepped up to Class One after dominating Class Three - and won at Silverstone last month in his first meeting in the 996 -  and should be a front-runner at Combe.The Class Two runners are the only Porsche Open drivers with points to chase, the leading driver of an eligible 996 GT3 Cup at the end of the season receiving a prize drive at a 2008 Porsche Carrera Cup meeting. Steve Rance currently heads the points table, but Combe could provide an opportunity for Mark Albutt to close in.Mark Chilton has been setting the pace in Class Three this season, his 928 GTS also providing a very different looking car for the Porsche Open grid. Opposition in class comes from John Fraser's 964 RS and Anthony Oliver's 993.Castle Combe will be a busy Bank Holiday for the drivers, with qualifying and two races all taking place on the one day.