Transmission tuning alone will do great wonders and unlock loss power due to the ECU systems being on high restrictions (because its a street car, doesn't mean it can't handle more just fine, but tuned for legal street driving).
The manufacturers manipulate the transmissions and drive train to be more of the "security measure" between engine and drive train output. This allows them (OEM) to factually boast numbers like the 400 HP/TQ ratings for the engine itself, but put more final power output control on the transmission and drive train. The average customer isn't even going to be looking that depth when buying a car, so its pretty easy to get away with. Plus it keeps the car more "in tune" with street safety, warranty periods, and the law. Street cars get a bigger tuning boost than performance bound cars do since they're more restrictive from the start.
For most, more HP/TQ = go faster. But it is more about how restrictive things are after the engine outputs its crank ratings (transmission and drive train losses due to energy transfer rate and ECU control). But the OEM have to somewhat "idiot proof" these high power engines after all. Otherwise raw 400+ HP/TQ would have people zipping into walls and off roads like in an old school muscle.
Once it gets ironed out, and we have a bit more aggressive 6F55 (and it will be fine, just keep the fluids healthy)...our 3.0T will be much more free with its power.
Edited by Zalvern, 11 November 2016 - 01:31 PM.