Three drivers have cut the early pace in the Porsche Carrera Cup GB, with two wins to Michael Caine, two wins to Tim Bridgman and four second places for Tim Harvey. Now, Donington Park is the venue for rounds five and six this weekend (3/4 May).Heading to Donington, just a single point splits Caine (Team Parker Racing) from Harvey (Red Line Racing) in the points' table. Caine was in fine form at Brands Hatch when the season opened and won twice, while Harvey has been consistent rather than outstandingly quick so far. Tim is always a contender and has chalked up for second places in all four races but he wants to win, and will be eager to bag his 18th Carrera Cup victory.Both Caine and Harvey know that, right now, the big challenge is coming from Bridgman, even though he trails them by 30 points in the standings. Having won three single-seater titles in recent seasons, Tim has followed drivers like Richard Westbrook, Damien Faulkner and Danny Watts in making the switch to the Carrera Cup to shift his career into sports and GT racing.But the opening weekend at Brands was a nightmare for the Essex charger and he failed to finish either race. However, Bridgman came back strongly to dominate the Rockingham weekend and show that he is a major title prospect. It will take some time to claw back the points lost at Brands, but Bridgman has time on his side, for there are still 16 races to run starting with two at Donington.The major challenge to this trio will surely come from Jota Sport team mates Sam Hancock and Phil Quaife. The team is new to the Carrera Cup and has spent the first couple of race weekends finding its feet. But the pace showed during testing at Thruxton two weeks ago suggests that the Jota boys will be bang on the pace at Donington. Certainly both Hancock and Quaife are potential race winners.Another driver bidding for a place on the overall podium is Charles Bateman at Team Parker Racing. He's part of the pace-setting squad headed by former racer Stuart Parker and is getting quicker and quicker as his experience builds. Adding an interesting dimension to the pro class at Donington will be young single-seater ace Callum MacLeod, making his sports car debut as part of his prize for being a finalist in last year's McLaren/Autosport/BRDC Young Driver of the Year Award. He drove a 911GT3 Cup car as part of the award evaluation process, but now gets the chance to race one and he's aiming to be at the sharp end of the field.Nigel Rice (Red Line Racing) should set the pace in the pro-am1 class, although the seasoned Carrera Cup racer is currently headed in the points' table by Tony Gilham (ReDesign Racing). Rice had a non-finish in the season opener at Brands after spinning into the gravel and is currently battling to overhaul the consistent Gilham.Joining the pro-am1 field for Donington will be Porsche dealer and seasoned race and rally driver Nick Whale (Team RPM), while another very experienced racer in the form of John Quartermaine will make his Carrera Cup debut at the wheel of the guest car in the pro-am2 class for 2007 model cars and earlier.After qualifying on Saturday afternoon, the opening race will be 9.50am on Sunday with the second race scheduled for 3.10pm. The second race may feature in ITV4's live coverage of the BTCC action in a programme running from 12.30pm to 5.30pm.