What is a good kit at a decent price (brand new)?
And what is a good kit at a decent price for a used car?
What electronics will be best (brushed, brushless, cells, etc.)?
I know these would apply to different tracks, but what is a good tire to start out with?
MO- I don't have all the answers, but I'll give you my opinion on some. A good kit at a good price is the Associated 12L4, soon to be 12L5 or other designation. Lots of places carry parts, it's fairly durable, and competitive.
Don't know about used car prices.
I would start with brushless electronics due to ease of maintainence, therefore more time to run. As far as choice, check out the racers where you intend to race to find what classes they run, and the combo of choice there. Same with tires.
Batteries will be 4 cell NiMH, and Ener-G and EP cells are probably a couple of the more durable cells currently offered.