I would get a CPO 328i, that's what I picked up for wifey and it's great. Got it cheap, still has warranty and plenty of left-over money for small modifications (I don't like stock cars). Had a 335i before the 328i.. I think the 328i is a nicer car to drive despite the lack of turbo power.
Also, have you considered a brand new E90 320i? 4-cyl turbo, fantastic fuel economy, great performance. join Trillium BMW club and buy the car @ Serpa BMW in Newmarket with Trillium BMW new-car price discount (Sepra only).
2530 Speers Rd #5
Oakville, ON Canada
Mon-Fri 9am - 5pm