OP,Listen to NovaBimmer and stinger9.
mango is expert on cooling system overhaul ...
Cooling system overhaul 1st.
Control arm bushing.
Rear trailing arm bushing
Rear spring always brake at 50k
Change vaccum lines coming from 2nd air pump to the back of manifold.
Oil filter housing gasket
Clean Disa - throttle body- carb cleaner.
Get NGK PLATINUM SPARK PLUG ($8 each)
New ignition coils
100k the oxygen sensor are gone.
Pentosin at oreilly for manual tyranny flush and red line fluid for rear/front differential.
Then you start to do mods and have trouble free car.
Honestly I can go on and on!!
Warning! Maintenance 1st are the Bmw will leave you in the road and drive you crazy with check engine light as this cars full of sensors all over the place.
Sent from my ZTE-X500