So far the Invidia Q300 is doing well with my 2015 Civic SI. The sound of it is not too loud especially when you're inside your vehicle. There is a little bit of drone but you really can't tell unless you pay attention. I'm recommending this part for those who are not looking for too much attention from the cops.
Sweet sound, but Not for highway use!
Everything comes with love and hate! Love: sounds great for cold start and gas pedaling Hate: terrible resonation cab noise on highway 70-80mph(1600-2000rpm) By the way , I install the rear exit at begaining, but it shows the pipe on the side which connected to the tips, that's ugly, the I switched to side exit, with I can get a bigger tip size! Some like 4"