I'm with povertyspec ... the M40 engine revs nicely, sounds good. If you have such a nice original car, then there's value these days in keeping it that way. So many 318i E30s are now long gone ... scrapped or converted. Please keep yours as it is!
I am of course biased, having a very low mileage Alpine White 1991 318i Convertible, with the grey check interior and shadowline trim. I wouldn't ever contemplate swapping out the engine.
Love your car, and will watch the project with interest.

















