battery doesnt increase the FPS, im only assuming that its 400FPS because its having the same range as all other 400FPS guns I have haha. my chrono's at my buddy's house. ill chrono it when he comes over.
in any case if you want lipo, here's what I used
http://cgi.ebay.com/Venom-Racing-Ven...QQcmdZViewItem
http://cgi.ebay.com/Firefox-11-1V-16...QQcmdZViewItem