S38 / M88... I've been thinking the E24 M cars look pretty interesting. Given price, performance, and collectability. However a respected forum pro cautioned me about the engines. Cautions include high cost of rebuilds (prob pretty well known), but also difficulty assessing health of an engine. A variety of failure modes come into play (going beyond timing component problems) and including shims jumping out and crank hub failures. Then, finally, difficulty in having confidence that a complex head rebuild is actually done correctly.
I'd be interested to hear some more discussions of such issues... How much risk is there of a $$$ failure for an engine that seems in good shape? Paul