The battery. . . and the fuel if you have a long enough siphon hose.
Listen, you've got to ask a better question. You don't expect a list of interchangeable parts, do you? Perhaps you are looking for a database with prices and sources. I'm going to suggest that you ask about a specific part and you start in the Shibaura forum instead of sticking your post on the end of somebody else's thread. You really need to narrow the scope of your question and ask it in the right place.