Welded is always better to avoid those annoying leaks, but a clamp will do the trick if you are looking for a quick, cheap driveway mod. It's really hard to go wrong with a muffler on an XJ, just keep your cat in place and almost anything sounds good behind it. I have had a cheap turbo muffler and it sounded great, then a flowmaster, also sounded good but a little too loud for my taste. And currently I have a DynoMax UltraFlo and I love it, just the tone I was lookin for. It's all a matter of taste, it's tough to make a 4.0 sound bad IMO!
DaFunk-95 Cherokee Sport 4.0/AW4/2WD/8.25
5" lift mostly RC stuff
CA Drop Brackets
31" Kumho AT's
All the usual go faster parts (still doesn't go much faster)
And a bunch of other stuff...
What does it all add up to? A bunch of wasted time and money. A bunch of time and money I wouldn't take back even if I could!