Just go to youtube and listen to different mufflers. Flowmaster 40 series or the 44 or magnaflow mufflers. I'm running a single in, dual out flowmaster 40 with a high flow cat.

 

All I can say is DAMN. My truck sounds wicked now. Super man growl on Acceleration. It took me and my lil bro about 7hrs to do the whole thing completely custom, a lot of up and down crawling under the truck but its was so worth it. I have to snap some pics. I also painted the whole thing from the y-pipe back with 2000° heat flat black paint.

 

Flowmaster Super 44's have a real aggressive sound when you gun it, and a pretty bad *** rumble. if you want true duals you will need to get another c/c. I would recommend two super 44's (1 in 2 out each) both cut and dumped down. That way the sound resonates all around the truck and not just directly out the back.