first you need a jr 8711 servo(403oz-in) or comparable at least in the mid to high 200 oz-in, second you should look into weather or not they offer a dig unit for it if youre not gonna run a sportsman class, lead for your wheels about 6oz in front and 3 oz in the rear the speed controller and motor should do good for now unless you think youre gonna need more wheel speed mainly crawling is about slow and steady besides you can play with your gearing, then if youre gonna use a dig unit you should know youre gonna need a 3ch tx and rx that is a three position if you want to use front and rear dig but you can use a 2 position if youll only be using front dig such as my buddies creeper that should do for now feel free to ask questions although im not an expert i may be able to help