the thing losi does with the preassemled is so a new guy in 1/8 buggy can just pick what engine they want and electrics ,associated does it to and ofna etc yea i also like to built the kit also, the 2.0 t has a longer chassis and longer wheelbase i belive , and 2.0 eight b i belive only really has a bit longer chassis ,if you run in a sportsman class a eight-t 1.0 and a eight -b 1.0 will still be competive in the pros dont know really