I recently replaced what was left of my muffler with a Cherry Bomb Glasspack. The back end and baffles fell out of my stock muffler and made it sound riceyer than the riciest ricer.
The Glasspack was the least expensive replacement part that any auto store had in stock, so being a cheapskate, i bought it and I really like it! It sounds pretty good on the 4 banger and has even seemed to open up the higher rpm's a little bit. I was pleasantly surprised that it wasn't as loud as i was expecting (with a name like cherry bomb and all).
This is the first replacement that has been an actual upgrade, so i'm pretty stoked. (i am the proverbial dutch boy and my jeep is the dike)
it even matches the body!
the remains of the stock muffler. (and sawzall blade)