A member of another forum recently dyno'd his 335i (N55) with the M power kit (the new kit claiming 35 extra hp). He has no other mods.

306 whp
344 wtq

This is the same engine used in the 435i. I believe he has RWD.

Someone correct me if I'm wrong with these comparisons:

If you account for a 15% drivetrain loss, the "estimated" crank is 351 hp and 395 tq. If you account for 20% drivetrain loss, the crank is 367 hp and 412 tq. It's virtually impossible to accurately devise numbers comparing crank vs wheel. I do know that wheel hp and tq are more accurate figures, not used by car manufactuers. With that said, these dyno numbers are very impressive. Either the N55 engine is very underrated, the PPK is underrated, or most likely both!

Great numbers.
Do you think BMW did any extra tuning and changes to the engine resulting in us possibly getting more from a kit like this?

I think they're constantly tweaking/upgrading the N55, perhaps the reason why Dinan can produce software tunes for the E series but not yet for the F. Just my novice guess. Those crank numbers I listed could be a tad inflated. Dinan uses a 12%/8% drivetrain loss which are known to be more accurate. Even still, 343/371 are great numbers. This guy with the 335i has the old PPK as well (20hp/20tq) I just found out. We can crunch numbers all we want and come up with various figures but, I'm sold on BMW's tune.