Anyone ever mess with these on a cooper s .If so what are the Pros an Cons if any...I would think it would tach up a lot faster but lose top end ...thinking about this app for AutoX..........

 

The use of a cutout to an open exhaust will cost you torque, thats what the backpressure is for. Plus you would need to be tuned seperately for the open setup in order to get the full potential from it.

That being said see this page:

https://www.northamericanmotoring.co...ps-etc-28.html

Post #691 & 693

Probably one of the best and most practical uses of a cutout that I've seen.