I spoke with a few mechanics whose shops have their own track cars and the consensus seems to be that what I am trying to achieve is not possible. The highest gain I have heard of was roughly 390 whp, a 100 shy of the e46 M3 GTR.
As far as the s65, it's not a downer, by any means. I have consulted with my father to rethink what our budget on this car is set at, and we're leaning towards finding an e60 m5 v10 and swapping it with that. I've seen that done a few places, not just online, so we'll most likely go that route since WE would not be "pioneering" the idea.