I dont think it will work. But I am not certian. The M3 is a 4 cly car and I would imagine that the tabs- triggers on the side of the fly wheel for the ecu would be wrong. The ETA engine gets its TDC - crank postion off the flywheel. So you need to be sure the magnets in the flywheel are in the same place. Then also make sure the bolt pattern is the same and the teeth count is the seam for the starter.