I heard the True Dual Exhaust setups have known to make the g's lose torque unless you are going or have FI. My question is how big is the piping on the Y pipes they sell and Single Exhausts. For example the Nismo isnt true Dual, how big is the piping? And how big is the piping on the Y Pipe? I went to an exhaust shop he said the stock looks like 2 1/4, so im guessing the aftermarket exhausts and Y pipes are at least 2 1/2. Just curious to know.

Thanks