The $50 box, transmits a signal accross the track, as the car passes the signal, it is picked up by the sensor in the car and then it feeds back to the hand-held unit. I don't have it on the car yet, that is what I am going to test this weekend. I am going to compair it to the ambrc system for lap times.

Pure speculation, I would say that in the future, the Spektrum people will have a lap counting systems that runs off this.