A PS3 kit is still the least expensive and easiest to install in a Protosound engine. They were designed for them and most of what you need is either already in the engine or included with the kit. That catch now is finding one. ERR stuff is a la carte. Receiver with motor driver is one piece, sounds a second, couplers a third, lights a fourth, chuff switch a fifth, $$$$$$, it all adds up. All that is in a PS3 kit.