Which used BMW 3 Series saloon should I buy?
There isn't a bad 3 Series - or even a disappointing one. The best two models are the petrol 318i and the diesel 320d, with the 318i preferable thanks to its lower purchase price. However, if you cover a lot of miles, then the better economy of the diesel car may be more attractive.
The 1.9-litre engine in the 316i is a little weak for a car of this size, and the 320d is worth the extra over the 318d. Gearboxes aren't a worry: manuals are slick, autos are smooth.