gas milage

do u generally get better gas milage with cat and muffler installed or with them removed? i would think removed because there is no restriction. but that would also affect back pressure wouldnt it? confused.

I'm not really sure if it affects it much. I never noticed a difference after I put the cat on my exhaust...

that'll depend on your car and how you drive it...

turbo's need as little back pressure as possible... i think n/a needs some..

Gas mileage and power are inversely related given the same engine.