HobbyPro has a few Bullitt parts in stock and at very good prices, but they no longer sell the actual engines. I have 2 Bullitt B-218 engines, which are the exact same as the OS XZ-B Speed - Version I. I just rebuilt both my Bullitts with OS Speed and few Ninja parts - basically all the parts are interchangeable. Bullitt came out with a new B-219, which I hear is the same as the OS XZ-B Speed II, but nobody distributes them in the US that I know of.