Problem 1: the battery placment.
I decided to run again the zx-r chassis because it is possible to choose the battery configuration you prefer.
Honestly I don't like at all the saddle configuration, so I have to found a way to secure the stick lipo battery.
My idea is quite simple, I use a small pice of teflon in order to secure the battery at the rear and I get some rc12 body mount in order to replace the standard battery ones because they are too short to use with a lipo.
I know it is possible to make a better holder, however using this solution I did not modify the chassis and/or any lazer parts, so I can improve the design in the future (probably the weight distribution is not the best available ...).