TJR
I have the Flowmaster 40 series delta flow mufflers on my car. I have to say they are much deaper at idle than the standard 40 series (2-chambers), but they are a bit quieter.
You are in luck.. I have my car up on jackstands now, so I will write down the part number for you in a bit.
To tell you the truth I got the mufflers for free from Flowmaster. Long story....
To me the straight through mufflers (glass packs) sound ok, but they are usually raspy and very loud. Mu buddy's 00 GT has them with a Hi-flow X-pipe and its pretty ******* loud, not to mention very bassy. I believe he has the Magna Packs on there. Plus the drone on his car is the worst I have heard. Installing a chambered design muffler will help reduce the drone, but yet so does an X-pipe. Also I think its believed that straight through mufflers give more hp, however minimal, but is it really worth it having it be way too loud? If you are going to dump straight through mufflers with an aftermarket H-pipe, be prepared to have every cop in a 2 mile radius hunting for you.
IMHO stick with the chambered design. My car drones, but I love it. The Delta flows didn't reduce much drone over the normal 2-chambers, it just changed the rpm range from when it occurs.