Exhaust System

I have a 2004 jeep tj columbia edition, with a 6 cyl. Was thinking of putting a muffler or some sort of exhaust on it to make it sound meaner, was thinking of putting a twister in it but a lot of people told me not to bother with exhaust systems on jeeps because they end up sounding like cars lol. Any suggestions on what I can replace the stock muffler and add on?
thanx

Friends Jeep is a 97 with the 6cyl and he has:

AIRAD
AIRAD TB SPACER
BANKS HEADER
MAGNA FLOW HIGH FLOW CAT
BANKS CAT BACK

It sounds great, not sure how it would sound with any of the parts missing tho. It is also a lot peppier now and seems to do better crawling in the rocks