I have one of the older Jardine exhausts, bought it in 2001 for my 01 from HVAC. Dont know if they still use the same mufflers or not, but it sounds great, no drone, not too loud to tick off the neighbors, but has a little bark to it. (sounds sweet when you are hard on the throttle next to a concrete wall or building). jcasper, not sure if your truck is the same as my dad's 06, but if they are, the exhaust is already 4" with mandrel bends, so you could just cut out the cat and stock muffler and replace it with a good straight through 4" muffler or straight pipe. (FWIW, i hate the sound of a 3rd gen straight piped) IMHO, the only trucks that sound right straight piped are 12 valves, but thats a whole different argument. :-laf