I just installed the new super 40's and I love the sound of them! Only complaint is it could be a little bit louder, especially at idle, don't they have to be given a little bit of time to break in all the way? or is this as loud as they will get?
It seems every system is fairly quiet at Idle. Not enough compression or cubic inch. Mine didn't start making noise at idle till I put my cams in. My idle is set around 950
I agree with tomustang. The cats, from what I've experienced - even high flow ones, keep the idle's rumble to a minimum. It should though "break-in" and become somewhat louder. Give it a little time.