If you are racing carpet then XRay. Asphalt is a toss up. I prefer Xray because of durability. I like the TC but dont like the fact that it doesnt have a battery strap, u have to use tape.
As far as parts go, im starting to think that unless you run Assoc, Losi or Traxxas, most on road car parts are not going to be available at most hobby stores.