Oh it will. Trust me. When I was cutting out my catalytic converter, i decided to ride around with a foot and a half gap in my exhaust system. Basically it was like driven a car with open headers! The fucking thing was so loud it hurt my ears! It honestly sounded like a prostreet car! I noticed a little bit of an increase in time (according to the trusty G-Tech) but i dont think its worth the damage to your ears, or the tickets you will undoubtedly get for excesive noise, or the nasty looks you will get from your neighbors, etc.