Looking to buy this unit, but had an important question that I need answered. I really need the audible speed limit alert. At what point does it activate? If speed limit is 60, will it go off at 61? What increments can I set, if any? I need it to go off at 1 mile over. My company runs Speed Gauge, and if it doesn't go off til 5 miles over, that would be too late. I'm allowed 3. Thanks in advance. I'm coming from a Rand McNally that was awesome, but finally broke, and don't have several hundred to replace it
