i'm running a dual outlet header, to a Y, to a flowmaster 40 series. it sounds nice and throaty while accelerating, but quiets down nicely at speed (which is my personal preference). if you want louder all the time, i hear the single chamber flowmasters are nice and throaty as well as glass packs.
'06 Wrangler SE, soft top, hard doors, 2.4L, rolling completely stock and unmodified for the short term...
'10 Wrangler Sport, soft top, hard doors, 23S package, Teraflex 2.5" spring lift, Spidertrax 1.5" wheel spacers. Sold.
'79 CJ-7 Renegade, 258 I6, T150, D20, D30/AMC20, 2.5in Rancho lift, 31x10.5 AT's, TeamRush upgrade, flush tail lights - Sold :'(