http://www.airsoftcanada.com/showthread.php?t=137820
Battery in the hanguard.
Id change the barrel too (its cheap like 40 bucks) you wont be disapointed madbull 6.03
For hop up you could go pdi w hold or prommy smooth rubbed with bridge tensioner or baton ryuski (or whatever the heck its called)
Or the all mighty rhop