Since exhaust sound preferences vary as much as other vehicle mod preferences , I'll let you know now that this post is for those of you who like a relatively quiet exhaust.

Because of my allergies I have a stopped up head that does not like exhaust noise/drone/resonance/etc. I had a Gibson 3" cat-back on my 97 5.4 Expy but the resonance at mid RPMs was too much for me (other people seemed to like it for the most part).
I got it where I wanted it by keeping the muffler but using 2.5" pipe to replace the 3"(stock was 2.25").

The muffler neck broke recently, this time I had a Magnaflow put on after reading posts here and talking to the exhaust shop owners.

The muffler is a 3" single I/O. I had them fit 2.5" pipes to it. They used the center/offset 5x7" oval muffler #12589.
(The center/center version #12579 is the one listed for the Expy but the installer thought he could get a better fit with the center/offset).

There is not a 22" muffler with single 2.5" I/O in the 5x7" oval.

So far I like it. Throttle response and good, seems a little better than with the Gibson but tough to tell at this point. Good sound on acceleration, pretty quiet otherwise. A little drone on the highway but not really bothersome. I'm thinking it's not much different than w/ the Gibson and I am just paying more attention right now.

Hope this is helpful.