Alright, I think it's time to do away with the single 5'' stack and go to a more realistic system. I have a 4 inch straight pipe exhaust leading to a 5'' single stack right now. Everything else is in my signature. I'm wanting a more quiet system that doesn't take up bed space so I'm lookin into MBRP. Basically my question is...should I run 4'' or 5, I'm definitely doin no cat but does the muffler really change power? If I went with a muffler how much power and throttle response would be lossed? Thanx guys.