[javadog]

BMW did not make it easy in those days to swap engines. I preferred the pre-OBD2 models, and in other brands as well, because there was less crap you had to deal with. l ended up changing the engine, exhaust, intake, radiator, radiator ducting, ECU, evaporative emissions crap, plus all sorts of random things to accommodate the different engine.

If you plan to swap out a bunch of parts, it may be worth buying something that's not worn out, so the parts that you don't use will have some value to others and can defray the costs of the build. I don't know that I would go much beyond 100,000 miles, because you'll end up where everything is pretty beat. It won't be a simple motor swap, you'll be into the tranny, the suspension and who knows what else.

I still think you need to drive one, before you even seriously consider any of this.