My Challenger had Walker Continental glass packs on it when I bought it. The sound, even from the little 318, was beautiful. Not too loud, definitely not raspy. They are long since discontinued but you can find old stock from time to time. I bought a pair on Ebay a few years ago to try once the Challenger gets back to that point.
I've never been able to find a good video or audio file online of a car with these mufflers. But it would be worth it.