Joe isn't far off. I bought an autosound, but it was for a truck!
My muffler shop got it for me. They had to build flanges for the 3" inlet and outlet to mate to my exhaust, but it works great. I did feel a slight difference, but mine was pretty well blown out, and I didn't have my muffler yet.
I just did some quick searching, and it looks like they changed their name to Carsound. My old receipt says Autosound, but it'* the same cat, and I believe it'* made for them by Magnaflow.
This link will get you started: