Nate, I would recommend AMB ( mylaps) mainly because many more racers have this transponder than the westhold one. Around here, I know Bethel and Lake Erie both use the AMB system. (as well as most of the DIRT sanctioned tracks) As for cost, I am not sure, but Joe Graf would be a good one to talk to as they installed the system at Bethel a few years ago. The transponders are expensive, but the tracks make a lot off of the rentals if they do it right. Much better deal for racers to buy their own. The mylaps website is also very cool as you can see not only your lap times, but all of the competitors.