I personally use 9.6v batteries.....massive NiMH ones.....5500 mah
but i would recommend an 8.4
with regards to the website, They are pretty overpriced and I believe people have been scammed there before.
http://www.airsoftcanada.com/showthr...ght=buyairsoft
check out what some of the experienced players have said about the website
EDIT: oops one too many zeros