I tried to get my weight bias to 70% rear and 30% front. I got it to 65%-35%.
With all the weight to the rear the car won't steer and it will want to just stand the front wheels up.
I also wanted to get as long of a chain as posable to keep it cool. I wish I would have put the radiator up front for even more weight over the front end because it still feels a little lite when I steer on the throtle.