The reason they say not to use any metal in your throttle linkages is RF Noise ( Interferance with your Trransmitter signal) I use Sullivan Flex pushrods ( Ny-Rods) for all my throttle connections. A z bend at t5he sevo horn and a ball link at the engine horn. Do not use carbon fiber rod on your throttle linkage either they cause RF noise also. The spring that comes with your engine is basically just a way to get a better connection between the boot and the plug. Just slide the wider end of the spring over the plug and install the boot until it fits on the plug real snug. Wrap the Shielded cord on your ignition ( The one the boot is attached to that has the metal braid around it) with the plastic wire wrap and use whatever is left over to wrap the black wire coming from the hall sensor ( the black magnet sensor on the prop hub) HTH, Rotten