I have check my Left/Right is balanced. :) With the above now I know my Front/Rear Weight Ratio is F52.5% : R47.5% (with battery at front position and added 50g front).
I know i said i dont like additional weight but D-Like designs are very far from TC-D (The motor mount location, wheelbase etc..) Until I get the brand new Maxpower battery design, I'll use the bumper weight.
Lighter rear + No front weight needed. :)