Exhaust
If you are looking for a good aggressive sound I would recommend Flowmaster mufflers...I had a 50 series put on about a month ago and it has a deep aggressive tone....You can hear the resonance in the cab with the 50 series for sure. :thatfunny Supposedly, the 40 & 50 series mufflers sound the same outside, except the 40 series is considerably louder inside the cab (much more resonance). I am really happy with the 50 series delta flow, awesome tone both inside and out. My 2 cents.
Good Luck...& Keep Truck'n
Later