I have a 2014 single cab with a 5.3. i gutted the third cat and deleted the muffler. left the little resonator at the back. NO drone in the cab, not loud at all out side just a nice mild deep tone. so mild i'm thinking about deleting the resonator too. these trucks are not that loud, i removed the whole cat back one day and drove around open y pipe. open Y sounded about as loud as my old 5.3 when it was stock manifolds cats and 2 flowmasters.

 

I just replaced my obnoxiously loud MagnaFlow 14" muffler to the dynomax vt 14". Both were 3" in and out. The vt is sure quiet at cruising speed and aggressive when your into the throttle. I absolutely love it. Look it up...I think you will be happy with technology price point, the sound and the performance.

 

Flowmaster 50-series SUV, true duals w/x-pipe. No drone.

 

Whatever you do don't get the dynomax vt it sounds great and no drone. However the spring probably won't last long mine lasted 6 months. If you don't have all your receipts and paperwork dynomax won't even think about honoring the 1 year warranty.