i had my test pipes installed today and all i can say is that they ar f>><<n LOUD it really woke up my nismo the only isue i had was the o2 sensor that is stripped and not sealed on completely to the pipe but tony at Fast Int said as long as there is no exhaust leak not to worry. Great Custumer srevice and excellent product. stand still rev is a little raspy but under load it is DEEEPPP!!! and Throughty but Loud i have 60 miles with no CEL and i really hope i dont have any issues with test pipes i never done this mod before.