Antigravity Batteries.
 

Just sharing some info here. :)

For those we are looking into saving weight (not money).
I would recommend the v-10 battery from Antigravity.
It's 5lb only, very very tiny, with cca of 720.
My mechanic burst out laughing when he saw it, and was doubting if it can do the job or not.
However, the purpose of it is mainly to start the car and save weight.
Definitely not for cars with heavily modified electronics.
For ppl are into tracking and save weight, not money, i would recommend it.

They are getting down to better pricing finally :)