I just put a used gmpp sport catback exhuast on my 09 today from a cobalt ss supercharged. Sounds amazing. The only thing i dont like is that the tip i got with it sticks out wayyyyy to far from the bumper other than that the exhaust fits perfectly. Thanks to those on here who have tried this exhaust on their hhr's and succeded with the install. This exhaust i would recommend to anyone that wants a deep tone with no raspy-ness.