all RTR chargers are junk. I mean, they work and get the job done but are slow.
A decent charger (like some of the ones linked above) will charge a 2s 5000mah lipo in 1 hour.
And there are chargers (for a bit more money) that can charge 2, 4 or 6 lipos at the same time.
Most any 2s 5000mah 30c (or higher) battery will work. Hobbypartz and hobbyking both have packs that use the same type of battery plug as the XTE.