Donington Park is the next stopping point for the Michelin Porsche Open Series, with a double header on Sunday 19 June during the Classic Sports Car Club meeting.The Donington date comes two weeks after a very busy triple-header weekend at Spa-Francorchamps and some of the teams will have been very busy in the intervening days.None more so than the Chimp Tune squad as it works to repair engine dramas in the 935 of Richard Chamberlain. Having won the opening three races of the season in style, it all went wrong for Chamberlain at Oulton Park with a first lap tangle with Peter Cook's 911GT2. Then, at Spa a cam chain failed in qualifying and his weekend was over. If all is sorted for Donington, Chamberlain will be a man on a mission.Rupert Lewin (996GT2R) swept ahead at Oulton and should have won again at Spa, had a minor incident with a slower car not led to a burst radiator. The 996 will suit Donington well, so another Lewin victory is certainly on the cards.Paul Howells (911GT2) and Keith Butcher (911GT3RS) are other notable class one runners, while Paul Daniels (911GT2) was a delighted winner in the third race at Spa after Lewin's retirement.Class two continues to be wide open, with victories already taken by Paul Hogan (996 Turbo), Simon Mifsud (911GT3) and Mark Stephenson (911GT3). Mark Allbutt is another promising newcomer to take the 911GT3 Cup route and joined Stephenson and Mifsud in a memorable battle at Oulton Park a month ago.Class three is equally competitive, with father and son Mike and Steve Burtt (993) setting the pace at Spa. Mike Johnson (911SC) belied his limited race experience to overcome Wayne Jackson's 944 Turbo at Oulton Park, but Jackson had previously done the double at Snetterton. John Allen (993 Super Cup) won at Castle Combe, but was out of action at Spa after an early accident.Finally, another excellent battle amongst the 944s is set for class four. Charles Winterhalder, Mark Harris, Alex Eacock and Tim Bevan have all had class wins to date, but it is Eacock who will be expected to set the pace once more at Donington.