When I bought my car it already had a Flowmaster Catback installed. I've always thought the mufflers were called 2 chamber flows but I've been listening to the sound clips on Mustang Exhaust.com and now I'm not sure. Maybe they are Super 40 Series?? I crawled under my car today and the only thing I noticed was the Pat number but that didn't help much. Can anyone tell me how to tell for certain what I have. I've used the search button with no answers so far.