ok this is a different question to Waz's...
I got a 3" cat back installed on Friday (hi-flow cat, 3" piping w/ 4.5" cannon) it's damn loud...as in I don't think I'll pass the EPA dB test.
Question is, how do I make it quieter? Or should I change back to 2.5"?
The other thing is when it's idling it sounds a little lumpy. Now the car's fairly stock. The only mods I'm aware of are the ones I've done (front mount, pod). There is also a Blitz BOV. Just wondering if this lumpy sounding idle is normal or does it sound like my car had some previous work done that I'm unaware of.