Similar stable of vehicles to mine.
E36 328 (close enough to same issues, track rat too)
E60 535 (same set of issues including turbos, just the box mine are bolted to is heavier)
E53 X5 (Ive got the V8 - you're choice for the 6 and MT is a much smarter, more cost effective route)
So, you should be aware of enough on these things. Take a look at ECS Tuning for some of their maintenance kits. This will give you a feel for what a suspension refresh would cost, or a cooling system overhaul, etc. They sell kits for everything now.
If it doesn't have a good documented history, plan on giving the car a good once over to baseline it. If it isn't leaking and feels tight, you have some time on your hands
Cheers.