So, you sick of having frequency conflicts with your buddies? Easy fix, mod your car to run on a frequency nobody else has! It's pretty simple to do, but you'll need some soldering skills. Here is the procedure:
1: Buy a
20Mhz crystal. They are less than a buck from DigiKey.com. I got mine from a junk 386 computer motherboard. (20 Mhz processor

)
2: I replaced the 27.xxxMhz crystal in the Tx with the
20Mhz crystal.
3: Re-tune the Bit PCB for maximum range on the new frequency. This is probably the hardest part because I had to melt the wax out of the tuning coil to get the tuning tool in to turn the ferrite slug in the coil. You MUST use a plastic tool, I got mine from a local electronics store - Radio Shaft may carry them too.
You don't need to tune the transmitter because it doesn't have a LC circuit on the output stage.
Other frequencies are possible, but if you stray too far away from the cars original frequency, you'll have to modify/replace the tuning coil and/or the capacitor across the coil to re-tune the circuit.
The mod didn't increase the range any, but then again - it didn't hurt the range either! I get about 12ft. before it starts to stutter. The test mule is a LXX clone.