The stock TT had 300hp at the crank, and after driveline loss people have dynod it at about 245 at the rear wheels. When you look at what percent was lost to the driveline it comes out to be about 18 percent.
I dyno'd 339.5 HP at the rear wheels. If you multiply that by the driveline loss of 18 percent, you get the crankshaft rating of about 414 hp.