Depends what you're wanting. For a nice but aggressive sound look at the BAmuffler setup. For a less aggressive but good sound the trd setup is nice. Flow masters are nice but I hear them on so many vehicles that I wanted something different
If sound is the objective then the BAmuffler budget system would work perfect. $349 shipped to your door. Completely bolt on. You can install yourself in your driveway in 10mins. The system includes: muffler replacement, rear gasket, helmholtz resonator for the tailpipe, clamps to make helmholtz bolt in, double coated with high temp black, and free shipping.
TundraTalk.net forum offers the most comprehensive collection of Toyota Tundra information. Find discussions on the Toyota Tundra Diesel, TRD Pro, SR5, lift kits, towing capacity, classifieds, and more!