you need a controller for them radders as they all electric guages as opposed to analogue.

best and by far the cheapest place to order them from is from a japanese whole salers called Nengun Performane, www.nengun.com

you'll have to register to get full shipping costs but the savings to be made are well worth the sometimes long delivery times (4 to 6 weeks sometimes) A fair few users on the SXOC have bought parts from them and have always recieved their goods etc. Good site