Hi guys, planning to have my first German car.

I'm looking at :

1) Audi A4 1.8L mid-late 90s
2) BMW E36 (316/318-320i).
3) Mercedes-Benz W124 Turbo Diesel.

What are the potential problem(s) i might run into with owning these cars?

What should I look out for when finally purchasing one?

or could you suggest a better alternative than these three (same price range please)?

Thanks in advance. :-)