Not loud at all. It is actually one of the quieter exhausts made for our cars. Although the performance improvement may be slightly less than the other brands. IMO, it is also one of the better looking exhausts made for the IS, especially since they made it 70mm piping.handy-man said:Is this system loud ? I don't want to sound like all the civics in my town, I was just wondering if anybody has this system and how is it ? Also, what did you pay for it ?