fluids are done at appropriate intervals (oil on these cars don't need to be changed every 3-4k, rather slose to 8-10k, yes i questioned this too!) They are great cars. My family has a e36 Dinan 3 which is a blast and is very reliable. There are a lot of things that can be done but remember this car is not a Z. You WILL realize this (not as quick turn-in, less power, handles different (No sports sedan based car can ever really handle like a sports car and I mean M3's and M5's), etc.). I suggest taking it to a reputable bmw mechanic and have it checked out first, then buy if it turns out okay. You can get a lot of valuable BMW info at [ www.bimmer.org ] and by joining the BMWCCA (BMW car club of America). Let me know if you need any more info.
