For HP/Wt ratio, I would go with a M52 engine out of a Z3. I read online that the M52 from a Z3 is lighter than a E30 M3 engine. Chipped and you will get over 200hp. I am considering that in my E30, fun, fun, fun. I love Mods:) No sure what the HP/Wt is of the M60 though. Where are you located? I may come help...LOL