Since it doesn't sound like you are worried about ROAR sanctioned events, etc. you might want to consider the Traxxas Velineon combo -- the motor and ESC go for around $160 or so, and I'be been racing against these in local dirt oval, and they seem quite fast and reliable... Like most Traxxas items, you should be able to get local hobby shop support if you have questions or issues...
"If you cannot win, make the one ahead of you break the record."
Biff Racing Team #420 (Ah... The "good old days"...)
The local indoor Offroad Track: The RC Race Barn
TLR22-3.0, TLR22T-2.0, TLR22SCT-1.0