for you question about lipos, redcat has hexfly 2s lipos.(they have the same style connector as the stock battery) the 5000mah or 5800mah ones will almost double the runtime and bump up the acceleration and top speed as well.
www.hobbypartz.com also has some nice 2s lipos that have the same style connector that the redcat uses.
they also have a thunder AC6 lipo charger. Its cheap, easy to use and will charger nearly any battery that a RC hobbiest will use. Its what i use, and u cant beat the price of $50.