heres some old enough i had if u would like to add.
The factory wideband system sniffs out the actual AFR and adjusts it to hit stock targets, if you add more air, it automatically adds more fuel. The thing that most people dont like, is that it stays at stock AFR's... The PROcede uses richer than stock AFR's, which shiv's says is neccessary to keep the engine cool. Keep in mind, its a Ratio... so the more air you add, the car WILL add more fuel, not like upping the boost on a non closeloop system... which will cause leaner than stock AFR's.
The TT hides the fact that boost is above stock levels, the ECU sees stock boost. The TT also tweaks the IAT sensor to trick the ECU into adjusting timing, and it does all this according to load. It also has built in protection circuitry to cut back boost if it gets too hot, and also to avoid boost spikes. (this is all info taken from the other threads)
Now if this is safe or not is subjective... many people think its fine at these power levels, and is proven by the fact that there is no detonation or pinging, and engine temps remain unchanged. Other's think that this device is completely unsafe...
I am offering completely unbaised info towards both products. Personally, since my car is a lease, and currently has frequent trips to the dealer, I have the TT... If I owned my car, and I didnt need to take it in often, I would definatly have the PROcede
and like mentioned by the op, some people do not give the SSTT time to adjust to the engine 100% and the dynos are not 100% accurate.
Jon from the Mshop can chim in aswell he knows alot about it and ran it on his own car.
Jeff aswell knows alot about it