RE: Roto start or Pull start
I think you need to ask on a specific engine or RTR model. I bought a HPIMonster King pull start recently and the roto start was an option. I like the KISS method. The engine is so easy to start with the pull start on this model I could not imagine a need for HPIto offer a roto start option. Its more of a pain in the ass to keep the glow starter on the glow plug since the engine is mounted on its side and the pull start is from the top.