The new McLaren P11 supercar is going back to the drawing board for a redesign to be masterminded by new styling chief Frank Stephenson.The former BMW, Mini, Fiat and Ferrari designer will join McLaren later in the year; he has to complete several months of gardening leave after resigning from Fiat in April.According to well placed sources, Stephenson will join McLaren Automotive to redesign the family of supercars that McLaren plans to put into production in 2009. “The basic engineering layout is fixed, but the styling is still open,” said one source.Images of the P11 first surfaced in the middle of last year, but sources now confirm that the production car will be very different. “It’s changed from those designs,” said our insider.That car was rumoured to have been put together to help raise funds from potential investors.Stephenson will also get the chance to design a rumoured open-top version of the P11 and a GTR race version. The latter may be powered by a 600bhp-plus V10. Both the open-top and GTR models are expected to be rolled out in subsequent launch years. The lightweight and more powerful GTR version of McLaren’s iconic F1 was the second best-selling variant. In an eventual total production run of 107 F1s, 64 were customer road cars and 28 were GTR racers.They raced with considerable success, including claiming an overall victory at the Le Mans 24 Hours in 1995. McLaren is understood to be eyeing similar success with a GTR version of its new supercar.The Woking firm has put back the launch date of its mid-engined two-seater by at least 12 months to accommodate the redesign. The preliminary launch plan would have seen the first P11 revealed later this year, possibly at Paris, or early next year at Geneva. Those dates are understood to have been delayed to later in 2009 or early 2010.The mechanical specification of the P11 has been fixed for some time as a Mercedes-sourced direct-injection 6.2-litre AMG unit mated to a double-clutch gearbox.