Tighten down your front axles to see if that will quiet down your bearings. I just had both of them wear out on my car. They started moaning 4000 km ago and the end result was one worn out wheel hub. It slid out of the bearing whereas it should have been an interference fit. The only other non-engine related thing I can think of are the brakes. Over the last year my brother has had all of his lines pop on his '89 with 300K km. If his mechanic was smarter they would have changed all the lines when the first one popped. My car has all new front lines and mastercylinder. The rear lines are next.
Anyway, there isn't much to worry with the body. The engine compartment is where I spend ALL of my time. Specifically, the wiring, the cooling system, and the v-belts. Carry new belts and tools with you. These things are not likely to last very long. Check the charging voltage to see what is going on there. Then go over the rad hoses, cylinder head flanges, and the metal coolant pipe. The metal pipe can rust out, the flanges can stop sealing, and the hoses can pop.
As for air filters, the Maehle filters are a lot thicker than the FRAMs so they should pass more air. I wouldn't bother with any washable filters as the paper ones can last a really long time.
Have fun!
Steve