A brushless system is recommended for this rig due to the axles . Anything from a 13.5 to 21.5 will work . I always preferred 13.5 so I can have the wheelspeed when needed . If you run 2S lupos you shouldn't need a BEC but going 3S you will . Only need 1 servo for steering as I am including servo for dig control . I do not have the manual but I can give you a link to one on Losi's website .
I'm interested in the crawler to mess around with the kids parks and such, no competitions. What would you recommend for electronics? Is a bec necessary? Do I need 2 servos? Do you have the manual? Sorry so many questions, but I don't have any crawler experience.