Originally Posted by Jeff@TopGearSolutions
Catless downpipes are not too bad. I guess it depends on how sensitive you are to exhaust.
At a cold start they are considerably louder, especially in a garage. On the highway they are very tame and I would say only a decibel or 2 louder over stock.
The only other time catless downpipes are clearly louder is when you go wide open throttle. However, even then to most it's a respectable increase in volume.
As always this depends on your sensitivity to modifications and noise. It may be in your best interest to visit the regional section of the forums and find someone locally that has a catless downpipe setup on stock exhaust and hear it for yourself.
good advice. some of the youtube clips scare me. I don't drive a civic