Whether I'd suggest alternatives is really dependant upon what you want from a car.
If you want 4 seats, good turn of speed, some of the best seats available and a predictable handling car, the 330 is a great choice. Having said that (despite owning one), I really wouldn't rate it as being the most fun I've driven, mainly down to it's weight.
Be aware of the costs too. Whilst pretty reliable, chances are you'll be buying a car without warranty. Mine has cost 1k in the last couple of years in unexpected issues (power steering pump, front wishbone bushes and new rear disks for the parking brake). Tyres were 450 a set and I average around 25mpg.
A few options could include:
- Alpina variant of a Bimmer. These tend to command higher prices, but might be worth tracking down one to at least see what you'd get for your dosh.
- By mentioning the 350z, that implies that you'd not too bothered about rear seats. If I were in that position I'd be inclined to checkout an S2000 (sounds ace), older Boxster (now available for under 10k) and for a left field suggestion a turbo'd MX5. None of them will have the refinement of a 330i, but I'd expect them all to be more fun.
- CTR. I know it's fwd and is in theory a "class below", however I really enjoyed wringing the kneck of the one I drove and it would be a lot cheaper to run (IMO).