[Power Adder]

I bought a 5000 2s about 8 months ago , and am thinking on buying another one for my conversion. Is this ok to do. Im trying to keep my converson light and small. Some people say you can get 20 hard min from a mm esc and a 8xl. I would go for the 6000s but i dont think they will fit in my next car (hyper 9)