[lincpimp]

Most buggies can get by with a 25c 5000 4s pack. So a 25c 2500 8s pack will have the same overall effect. Most lipos from the same mfg have the same energy density, so go by weight. So if the 4s pack weighs 500 grams, a 6s pack that also weighs 500 grams will provide the same runtime, if the motor rpm and gearing are setup the same for each setup.

Most people stick with 4s as it is easier to find a solid 4s esc than a solid hv esc...