Enjoy folks. 335 GT has Active Autowerke Active8 Tune which adds about 60 crank hp and 40 wheel. The 355 hp X4 now has at least 400 or more, as it's only a beta tune for that specific model. Aerodynamically, the GT has the upper hand in the triple digits where it starts to catch up and reel the X4 in slowly. Though, from about 70 to 100 pretty even.