You'll have a job to find a decent one at that price. In the end I went for petrol because I was scared of the diesel's long term reliability. Paid £8k for a Msport one with sports leather and 85k. That was before the crunch bit though, you may do better.
edit:
Just been poking around and remembering why I changed my mind from diesel

Pre-facelift 330 is 184bhp, and the later diesel is 204bhp but comes into the proposed new car tax ratings.
330i Petrol was 231bhp from introduction in 2000, no turbo, less to go wrong but of course fuel consumption is heavier - but much better than an E30

Honest John has a review with info here
http://www.honestjohn.co.uk/carbycar/index.htm?md=36