I'd never buy a used nitro RC car personally, because you have no idea how bad the engine was tuned, how hard it was run, and how it was broken in, if at all. Not much of a difference between the two, maybe some small parts, but yours looks pretty well upgraded, so no problem there.
It seems to also have some Tekno RC parts on it, as well some metal-bodied shocks, a metal muffler, and a larger gas tank. For cleaning it, some Dynamite Nitro Force or some other RC nitro cleaner and a brush would work magic. As far as an RX battery goes, I would suggest a Venom 1600 MAh flat 5 cell pack
http://www.venompower.com/collection...r-nimh-battery