The contest for the Porsche Carrera Cup GB is set to go down to the wire as Tim Harvey and Richard Westbrook go head to head for one of the biggest prizes in British motor racing. Heading into the penultimate weekend of the season at Snetterton on 4/5 September, just five points split them at the head of the championship standings.The Snetterton weekend marks rounds 17 and 18 of the 20-race season and will be a highly critical time for Harvey (Team RPM) and Westbrook (Red Line Racing) as they compete for the £55,000 Porsche road car that awaits the champion.The season-long battle between these two fine racers took a dramatic turn at Brands Hatch on 22 August when Harvey finally suffered his first non-finish of the season. Starting race day at Brands, Harvey had a seemingly secure 29-point championship lead but by the end of the afternoon that was down to just five points. Westbrook is right back in the title race.A puncture in the opening race at Brands forced Harvey out and left him starting the second race from the back of the grid. Though he tigered through to finish sixth, Westbrook bagged two strong podium finishes to slash the points advantage Harvey has enjoyed since Westbrook's non-finish at Brands back in April. "We were always hoping his bad luck would come and now it has," said Westbrook. "Now it’s a level playing field!"With up to 43 points available across each pair of races, the title race has been blown wide open and it is now a straight fight to the finish at Snetterton and then Donington at the end of September. Even the extra point for pole position in qualifying and fastest lap in each of the races could be crucial.However, Harvey and Westbrook have plenty of rivals in terms of race wins. Jason Templeman (Team VLR) was peerless at Brands with a double victory after a run of misfortune and he can win again at Snetterton. Jonathan Fildes (TCR), meanwhile, is another strong racer who has just got quicker and quicker as the season has developed. Along with Nigel Rice (Red Line Racing) and Andy Britnell (Motorbase Performance), Fildes will be battling Templeman for third in the championship standings.More than capable of taking victory at Snetterton is Damien Faulkner who has joined the Motorbase Performance team alongside Andy and Gary Britnell. Meanwhile, Chris Cooper (Team Parker Racing), Marcus Thomas (Team VLR) and Jason Young (Red Line Racing) are all showing top six speed.But all eyes at Snetterton will be on Harvey and Westbrook. This contest is now wide open and there is a great deal at stake!Provisional championship positions after round 16:1 Harvey 273; 2 Westbrook 268; 3 Templeman 196; 4 Fildes 184; 5 Rice 164; 6 Andy Britnell 149; 7 Young 103; 8 Gary Britnell 98; 9 Cooper 93; 10 Thomas 86; etc.