Lets talk about batteries

[psycho]

Hi!
I am fairly new to the hobby. I got some nitro cars but what got me hooked to the electrics is my Mamba 8000 18T. It kicks a lot of nitro cars.
I understand that voltage is a measure of power(charge gradient), and amperage is a measure of current(quantity of energy flow).
I do notice that when I run the 3300 batteries on my Ezilla it surely run quicker and faster(also longer time) compared with the 2000 batteries. Now that I plan to run it brushles and lipo(I expect it will not hold for long), I got a question.
A 5s 4000mah would be also quicker and faster than a 5s 2000mah lipo in the same way as the Nimh? Or only the run time will be longer? What lipo set up would be better?
A single 5s 4000mah or 2 5s 2000 in parallel?
Thanks:devil