i have one and haven't had any of the problems supposedly associated with that year, except for the headlight covers going foggy and, of course, the misaligned glove box!
here's something i found:
Driveline:
- Water pump will need replacement because of the plastic impeller (M50)
- Radiator - look for cracks in the plastic neck
- Defective ignition coils in some of the '91 and '92.
- Drive belt tensioner
- Profile gasket on the earlier 318's (M42)
- cracks in plastic thermostat cover (M50)
- sticking thermostats (M50)
Suspension:
- Outer ball joints go bad
- Rear shock mounts go bad
Interior:
- Window switches
- Door panels seperate because of insufficient glueing
- Dashboard vinyl can seperate over the center vent
- Seat heater elements break
- Glove boxes misaligned - especially earlier models
- chipping trim around the tweeters in the front door panels
Exterior:
- Plastic headlight covers get foggy over time
Misc:
- brake light switch