I just put on a "silver bullet" glass pack last month.. hehhe it sounds too cool to do less than 4500 rpm shifts.. so my fuel mileage has suffered, but I cant stop laughing. Its worth it to me. I still have the Cat in place so its not to noisy. Fuel milage when Im driving nice is about the same as before. The pack makes it easier to wheel though, theres less for tree stumps and rocks to grab. The turbo muffler I had on before didnt last 6 months, it was beat, and punctured.