Get some Magnaflow highflow cats, y-pipe and 3" pipe all the way. That's what I'm running and it's pretty loud with very little drone. I've been considering going to a SI/DO setup like 08FX4's but I'm not sure I want to go that loud

 

i got the 3 1/2" catback , magna pack, exiting out a 3 1/2" dump in front of the rear passenger tire. same issue , sounds beast at low RPM ,check out that 4th gear at like 1K rpms ..sounds like a 427..a lil. either way man i think thats the nature of the exhaust . obviously true duals will have a different deep tone through a different range, in a better way. but ur gona have to cough up 1200 compared to our 600$ systems. btw i used to live in sanford , go to SCC in lake mary. good stuff.

 

^ The dump is your problem. Run an exit out from underneath the truck with some 18" long tips.

 

even with 3" intermediate piping and split 2.5" tails it still does it, i like it so its not a problem. maybe get high flow cats, 08fx4's old truck had that setup with dual tails and it sounded deeper then stock through all ranges. And yes you will have drone regardles