hey, im new to the civic and was wondering if anyone new of a full exhaust system that provides a boost in horsepower but doesn't boost decibels? i'd like to find a system either as quiet or almost as quiet as stock.

The problem is most exhausts try to be a little loud. I have a magnaflow on my 02 Si and it sounds great. It has nice low sound at low rpm's but doesnt get too loud as I wind it up. Im not sure about their regular civic exhausts though. The bigger the muffler the quieter the car is going to be. So you could e-mail a bunch of companies that sell exhausts for your car and get some dimensions on their mufflers and that would give you a decent idea about how loud it would be.