Money aside, the V1 is powered by a simple phone plug, so it's easy to run some wires in each car.
Also the V1 has the best performance and is probably more advanced than you would think. It's the only one that would actually point an arrow to show you were the signal is coming from and it can count how many threats are out there at the same time.
Often the police would be in a location where there is a lot of interference for detectors, other detectors would either mute that location or you wouldn't know there is an added signal which is the police officer without the V1.
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