[Anthony B]

I would agree with Chris and Brian - if you are going to run 'out of the box' cars - and NOT the high performance cars like NSR, then a 45 OHM would be best on a tight track.

Best investment would be a slot.it type electronic, so that when you buy that 'must have ' car that happens to be high performance, you have the controller to handle it.
Wrong ohmage can create the controller to act like either an on/off switch, or if motor too strong and and ohmage high, cause the controiller to burn out. (last 2 examples are extreme and unlikely to happen with over counter cars - used for examples of mis-match only)

Welcome to the forum!!!