Plot: REVIEWS: Audi RS6 • Mercedes-Benz E55 AMG • Maserati Coupé • Ford Fiesta • Citroën C3 • Honda Jazz • Nissan Micra • MG ZR CHALLENGE: Lada Riva modified by Lotus • Fastest white van man This week: 'driver's cars', the BMW M5 faces the challenge of its rivals, a Lada Riva 1. 5E gets a make-over from Lotus and who is Britain's fastest van man? Also featured are the Audi RS6, the Mercedes-Benz E55 AMG, the new Maserati Coupé and a selection of super-minis: Ford Fiesta, Citroën C3, Honda Jazz, Nissan Micra and MG ZR