REVIEWS: MG XPower SV • Porsche Cayenne Turbo • Mercedes-Benz SLR McLaren CHALLENGE: Which professor can do the best burn-out? • What is the best British car? As usual the boys are squabbling about cars. This time they can't agree on which is the best British car. Jeremy says it's the Noble M12GTO, Richard can't see past the Morgan Plus 8 and James, in a moment of utter madness makes the case for the... Rover 75. Back on planet Earth, well, South Africa, Richard drives the new Mercedes McLaren SLR and the Porsche Ceyenne gets the benefit of Jeremy's scorn and delight. He also drives the MG SV - a £70,000 car built to compete with Porsche - don't laugh.Boffins, Brian Sewell, Colin Pilinger and Heinz Wolf try a 'burn-out' and Rory Bremner is the Star in a Reasonably Priced Car.