I use an ancient cobra brand detector- it picks up false alarms, but it sees cops on the highway long before i do and it's usually pretty good about it.
For some reason, the detectors we have in our 3 and 5 will act like they're picking up a laser when we accelerate or go up a hill. Doesn't happen in the protege or our elantra...
...my dad assumes they never really picks up radar or lasers at all; they just have some crude sensor in them that knows when you speed up and the idea is that the alarm goes off when you speed up and you'll slow down.
My idea is the 2.3 is emitting lasers- i like my idea better
edit: i also have to add that i never go more than 2 mph above the speed limit, at least on the highway. I don't need a detector, but it's fun when it makes all the alarm sounds when i start up the car.