I have a 450 Foreman 4x4 with 27 x 12 x12 Vampires all the way around and a lift kit. The engine is bone stock and i really don't have any complaints about it, but I would like a little more power to turn the tires over as if they were the stock tires. I was looking at a few simple upgrades like cam, muffler, and jet kit, well the jet kit I have already installed, it is made by Dynojet. Some information on the muffler and/or cam would be very helpful.