Since the TT50 engine is going in the 2011 lotus
(
http://www.autoblog.com/2008/02/16/2...twin-turbo-v8/)
and the next M5
(
http://www.worldcarfans.com/9080708....rbo-v8-from-x6)
I suspect TT50 base engine will be used for a lot of models, you could increase the X6 hp by just upping the boost.