I have been dying to find any mention of what they will be able to get out of it and finally they are beginning R & D. In fact, if someone is lucky enough to get one in the immediate future, they are seeking a test mule. See below from Dinans site:

DINAN IS SEEKING AN
'09 X6 50I FOR SOFTWARE DEVELOPMENT!
The vehicle will be needed for approximately 1 week and the owner will receive Dinan Performance Software valued at $3000 absolutely free! Ideally, we would like to have a vehicle by August 4th. Contact a Dinan Performance Representative for details at 800-341-5480. Don't miss this opportunity to increase the power of your X6 significantly at absolutely no cost, and it's backed by Dinan's matching new car warranty coverage for up to 4 years or 50,000 miles.

I am betting they can go north of 500HP without a problem.