Apparently Hartge did drop an s62 into an e46 m3. They call it the Hartge H50. They also dropped one into a z4.

Here's Car and Driver's article on the H50.

http://www.caranddriver.com/article....rticle_id=3485

Heres the z4 one.

http://www.m5board.com/articles/germany2/hartge2.htm