Not a complete answer to your question but this might help
Batterys LiPo NIMH
http://www.rcgroups.com/batteries-and-chargers-129/
They are a mostly focused on RC Airplanes but by far the most knowledgeable, in depth discussion of batteries and chargers on the web.
EXEC Sum: Li-Pos have all but replaced NIMH in the last 2 years, primarily because they are lighter and unlike NIMH the don't seam to weaken with each successive charge also they tend to give out there full voltage over the full course of a race. The prefered way of charging Li-Pos is with a balance charger which essentially charges both cells (7.4 volt Li-Po = 2x 3.7volt cells. equally so both cells end up with the same volt. You can get a pretty sophisticated multi chemestry (NICad,Nimh,Li-po) computerized charger from Hong Kong for less than $50 or US branded equivalents in the under $75 price range. (check out the above URL for discussions of various models) ROAR and most organized race programs are going to want you to take precations like using a battery protected by a hard shell plastic case and to charge the battery inside a flame retardent {LipoSack}.
Brushless motors have also replaced brushed motors more or less, because they require little or no maintainence. You will need a brushless Electronic Speed Control. You can visit the various manufactures web sites and view some threads here. Pretty much it is matter of deciding which class 13.5, 17.5 etc they run locally that you want to run in. Its tough to go wrong with Novak, Tekin or Orion.
Chassis Just choose one of the competitive brands and pay your $400-500. Then find the thread for your model here on RCtech, read it from the start and then ask questions. Tough to go wrong with X-Ray T2 , Hot Bodies Cyclone. Dual belt have replaced single and shaft competitively.
The changeover to Lipo/brushless has caused some uncertainties about class definitions(what to replace mod,19t,stock with) they are sorting things out with lower weight minimums and different 'turns' of brushless.
Also foam tires indoors are fading in popularity in favor of rubber tires.