We have started a class at our club with 4 cell specs.
4 cell sedan :
4cell max 4300mAh
3.000lbs (1361g) min weight.
5mm min ride height
4 door body
4wd commercially available 190mm electric sedan.
Foam or Rubber tires
Stock Motor (P2K2, MHP, CO27...)
For example :
A 6 cell sedan with a P2K2 the roll out is about 27mm (on our local track) in 4 cell the roll out is about 37mm. the 4 cell cars are 1-2 laps down from the 6cell A-Main times. the 4cell car setup is NOT faster then 6cell stock sedan BUT its not far behind.
As for weight distribution, I have tuned a fellow co-workers PRO4 to run 4 cell, the car was previously tuned for 6 cell, all I did was adjust the preload and verified the tweak and droop. he is running fairly recent electronics (lighter) therefore the removal of 2 cells actually make the car somewhat close to be balance properly anyways...
I strongly support 4cell sedan as an entry point for racing because the 6cell stock sedan is not the same as it was 10 years ago (they are faster), the TL01 spec class is not in effect anymore at our club, racers buy one race car, race the first year in 4cell and then the second year they can choose to stay in 4cell, move to 6cell Stock Sedan with Rubber tires or 6cell 19T Foam tires sedan.