2 trucks are race breed, 5 trucks are bashers. One is not designed to compete with the other. Racing- GT2 or XXXNT/AD2 both very close. Basher- buy what your LHS stocks parts for. Try and decide bash or race you will spend $$ more wisely.
Race vehichles can bash but more fragile. Bashers can race but built in flex( to reduce breakage) make them not race friendly.
And if its only about speed find a second hand AE FTGT go to New era on line and get .21 conversion or buy Shumaker gas truck comes with .21