You might be suprised. Take a look on this thread and scroll down. The Porsche units do well and I wouldn't discount the Audi unit either - a RF with one took top dog at Run and Gun, gear box is good still.
http://www.gt40s.com/ubbthreads/show...4590#Post25038
Just don't treat your GT40 like a dragster and you'll be fine.
R