you know what will really make that 304's exhaust sound sweet.... A loapy cam..
I would honestly say sound is secondary to performance in my book. loud exhuast is just that, but if the person that you want to hear it is in front of you because they are faster, that loud exhaust is null and void.
I personally prefer glass packs with some type of resinator when considering the sound.. but I run a 8" dynomax circle track glass pack on my YJ... it's sounds pretty decent, I get a lot of popping after a hard throttle though.
Lastly if you really want loud exaust, get some zoomies.