Miles Nicest

Would you recommend buying a 2002 330ci with 100k miles? It seems nice but with that many miles i don't know. ?

we got a carfax with 4 previous owners. no other problems though. We are taking it to a mechanic but are there any other problems or concerns I should worry about?

That car will still be running strong after 400K.
The 100k rule usually only applies to SOME little 4 cylinder engine cars.
The BMW 330ci has a straight 6 engine (which has been tried and tested in other model BMW's) and is amazingly reliable. Also, the 330 is supposed to be the tuned up version of the old 328's, so even if it has been thrashed about, its ok, because that is what it was suppose to do.

One thing you need to make sure of is it has service history by BMW, No car, regardless of make, will last if it has not been serviced regularly.