I was thinking of putting an electronic cut out on my 2003 mini cooper s. I don't know if this is going to hurt me or help me. The sound is not that big of a deal to me, but the performance and gas milage is. Do I want the back pressure or do i want the cut out?

 

most modern engines need backpressure no pressure lost performance

 

That is what i thought because of my last car, but my last car wasn't boosted. I thought that a open header would be best so that you can build that boost faster.