I,m going to give an inferno 7.5 sports a try

I have 2st 2s 8000mah maxamps packs that i'm going to connect i series to make a 4s pack or maybe one 2s an one 3s for 5s pack? or i might go fore a 6s2p A123 2300mah cell pack (2p=4600mah tot !! )
But i don't know if i choud go for the usual setup with a 8xl motor an 4s lipo packs :)insted because this is my first electric conversion so i might be better of with a proven setup that i know works great ? or what do you guy's think ?