And get yourself the JP-4 pipe rather than the JP-2. Much better overall pipe and better on fuel too. It also seems to work with virtually every engine we have tried it on, so good for when you need to upgrade the engine in the future.

As for the Mac, I found that on my sons car, when I removed the pull start and put a bump start on, the engine ran a load better, it was like a different engine. As Kal said above, when you run against a good race 21, then you will see how poor the Mac actually is.