TTI exhaust too loud

Great thread, but one question remains: What constitutes a "sleeper?" I have seen a Duster run 12's and you can barely hear it going down the track. Guy got the car on trade and had no idea what exhaust he was running. It looked like a basic dual set up, cheap headers and stock mufflers.
My Duster: Hooker headers, 2.5 pipes with Dynomax mufflers. TO LOUD LIKE EVERYONE ELSES here. Originally had Flowmasters, went to Magnaflows then the Dyno's and I did not notice a difference between the 3. It is draining/exhausting to drive. I dont have a trailer so I have to drive fair distances to small car meets or to the track. I have no idea how much Fatmat or Dynamat would affect the unbearable drone etc at highway speeds. It's ridiculous wearing ear plugs, so WHAT DOES IT TAKE TO MAKE A SLEEPER?