^ya, but your driving the car with another display, so the miles are adding to that one, and not your original one. You put the old one back in if you ever sell the car, and it might read 100K miles less than what you actually drove it. Or you leave the newer after market on in there, and only have 50 or 80K miles on a car that's like 15 or 20 years old. Don't say anything...or note it...its against the law pretty sure.

~F~