And about the turner M3 using the S62....just going off what I've read on the boards over the years, since the S62 was used in the M6, it made sense to continue with the S62 in the M3 in terms of cost and development.
In rolex, the daytona prototype and GT class BMW both use a S62. The S62 is the only approved engine for dp, not sure about the GT class.
http://www.grand-am.com/Portals/0/Im...%201.16.13.pdf