the choice given would have to be narrowed down to the following in order...
durga
501x
zx5
xx4
the durga is a good competitive car for starters being low cost and spare parts are available cheap for it and when you may have the need to upgrade to a more expensive car you have the 501x (daddy of the durga) although parts for the 501x are expensive and hard to obtain the car is neutral and easy to drive for most people
kyosho zx5 is also a good one for starters as spare parts are again cheap and also easy to get hold and the car again is just as competitive as any other car on the market
xx4 is fast but can be car known to be unreliable for stripping belts and plastic parts made out of cheese
spare are easy to obtain for it though and at good prices
hope this helps abit,