My terrible experience with aFe POWER ... Check Engine Lights & Poor Customer Support (1 Viewer)

[YellowLab]

Sorry this has been such a PITA for you

 

[cmfhsu]

Agreed, you can probably make the same argument about restrictive exhaust. The engine will call for the same torque demand but you may increasing the curve on how fast it can ramp up to that same demand.

Cat back exhausts on a turbo are more or less no meaningful extra power, but reducing the restriction from the primary cats will absolutely make a huge difference.

You will also fail every smog inspection and have a check engine light unless your tuner turns it off.

Exhausts are a bit of a different story because the engine has no meaningful way to control exhaust flow / restriction, whereas the engine will simply close the throttle plate or open the wastegate if it's getting too much air.