Originally Posted by mf07sti
Do not get a q300 if you are looking for a quiet exhaust with no drone. I used to have and would highly suggest looking at the maddad whisper exhaust. I ran that for 4 years prior to the q300 and it was a night and day difference between the two as far as sound goes. With the whisper you would never know the car had an exhaust on it under light loads, however it quickly opened up on throttle. With the q300 on cold starts it will vibrate the springs on the garage doors that are about 5+ feet away from the back of my car. The whisper is a little expensive but they are made here in the US which was nice. If you good to the website it won't say they have but you can use the 08+ Sti and it will fit.
Maddad was at the top of my list when I was looking into this a few years ago, but I was reading that they weren't responding quickly (or at all) to email, etc. Their website also wasn't very up-to-date (e.g. it should state the 08+ STI would work with '11 WRX hatch). Anyway, it sounded perfect in the videos but the price is pretty bit high, especially since it is a cat-back option only. Thanks!