Now I know there is a thread on a similar topic so before flaming starts watch this vid! It is a must see.

Its in Japanese and there is a long intro with some nice footage of other fun stuff testing on the ring. (Even what looks like an AWD Ferrari 612 among others). But in any case here is the info I could decrypt:

3.8L VQ V6 TT 450hp AWD
6speed sequential

The best part is after the 2min mark when they start showing the Nurburgring testing. They have some bits where they overlay 997tt and GTR video side by side through corners for comparison. GTR is hanging in there quite well from the looks!

http://www.youtube.com/watch?v=ZmyYqO5jtFs