All this big power is great, but the M3 is just not the platform for it IMO. The M3 is great as a 500hp car, when properly tired up. Beyond that, you need AWD for anything other than a rolling start drag at an airstrip. From that standpoint, I think the GTR and 911 turbo are untouchable as big power modding platforms.
Audi S6 * Audi S3 * Porsche Cayman GTS
--Former BMW M3 owner