I think Steverino is pretty close to right. Remember, the OEM halogen bulbs are only about 55w each. Not sure exactly what the draw is on the LED bulbs, but you're saving maybe 75 watts by switching. Figure out how far you'll go on 75 watts and that should give you a pretty liberal estimate of what added range you can see. Personally when comparing to the trouble that some people have had with the LEDs creating issues, I'd be more comfortable "wasting" 1/10 of a mile range just to avoid.