One of the most cost effective ways to increase the performance of any gas powered Rampage is the addition of a good quality tuned pipe. I offer some affordable aluminum pipes that are okay for the money but they aren't the the best in terms of durability. The Catbox is very durable and sounds great but isn't the best for all out performance.
If you want the best performing pipe that is also extremely durable, check out the pipes offered by Dino over at JetPro. He has pipes for all models of Rampage in your choice of chrome or raw finish.
Let Dino know that Rob from RampageShop.com says his pipes are the best!