Bro,
These are the things I will do if I were you:-
1. Check full details of car by keying in the VIN
http://www.realoem.com/bmw/select.do
2. Take the car to any of the reputable BMW workshops and have them do a diagnostic test, check suspension system, any leaks ( from engine, auto-transmission, steering rack etc).
3. Get an estimate from said workshop for the above repair.
4. Then nego price with the car dealer.