What DaveG55 said is so true. The telemetry gear on your RC will be a hinderance as far as weight is concerned when you are actually racing (I am speaking about 10th scale on-road cars, I dont know if that gear will affect larger scale cars and trucks as badly).

IMO, telemetry is okay to have when you are practicing so you can perfect your driving style to get better lap times based on what the telemetry tells you. But during actual racing, you are probably better off taking the the telemetry gear off your car.

Now, the Nomandio Sensor has telemetry built in to a receiver (actually, a tranciever) and that integerated unit would be better if you wish to keep the telemetry gear on during a race. However, the Sensor could put you back as much as $500 (I do not know what they cost now, they might be cheaper).