I just purchased this exhaust and raced this weekend with it. I am very, very pleased with it. For the type of riding I do (hare scrambles, woods, trail riding, etc.), its perfect. However, if you don't care how loud your bike is and/or feel you need EVERY ounce of horse-pressure your 450 makes, or you're worried about how much your exhaust weighs, this probably isn't the system for you. If you are very sound conscious, or ride off-road/woods, check it out. NOTE: The exhaust I had been running on my '08 was the stock header with an OEM '07 muffler, with a ProMoto Billet spark arrestor. Here's the link to my review.