I also got one, I tried putting one in my JRx-s, you really have to keep the wires away from all the moving places. As for the lap counters you can get them on e-bay for $49.00 new, I think thats retail. But everyone only needs one per track, the sensor on the side will work with everyones car, just like thew counting computer. It might work better in my nitro truck were you need to work about temp and voltage a lot more, the monitor also weighs enough if you have it on the top of your radio.
Owning a lot of RC vehicles doesn't always mean a lot of knowledge.