Carcraft are cr@p. They buy cars from auctions, dont do any work on them then flog them on. Give you a warranty and if it breaks theyll (might) fix it if it dont then they saved even more money!
Pistonheads is good could do with some more search options on there. Just bought a car off autotrader from a garage got a good price and a good car. Parkers is an excellent site for checking reviews and performance of a car and everything else you want to know and also search for the car you want.
www.parkers.co.uk