HOLY S#*T is this thing loud! I had an Apexi N1 on my 2007 Civic Si and this is deff. way louder than that was! It sounds great but man I did not think it would be louder than my Si was. Again I think it sounds amazing and I don't mind the loudness myself but I am actually worried about getting a ticket with this exhaust lol. I had my dad listen to my car as I drove up the street and around the block and he said it wasn't too loud and that coming from him is strange b/c he hated the Apexi N1 on my Si. I also did the same thing with my girlfriend and she said it's not too loud either... it's just so deep sounding compared to my Si it just seems louder. But again I love the sound of it! To me the drone isn't bad b/c I'm used to my old Si's exhaust. Fit and finish is great as well... only real complaint there is the rubber hanger things make the exhaust move a little bit so every once in a while it gets kinda close to the bumper.
Just wanted to give a little bit of a review of the Invidia in case anyone else was interested in getting it for their 2009.