I have a cat back exhaust and 2.5 inch high flow cat and stock down pipe. right now my exhaust is as loud as i can take it. will adding a downpipe make the exhaust much louder? how about droning issues? anyone who is an expert in exhausts know?

 

i had just an AMS catback on my 06 mr. Then i put on a HFC and downpipe and it was only a little bit louder at idle. Not really any louder while driving. So just a donwpipe will not be much louder at all.

 

It adds little vibration under the front seat due to the dp. But I couldn't really tell with Megan DP, UR HFC, Greddy SP2

 

I will be partially louder.