DIGITAL SPEEDOMETER WAS 35 MPH OFF WHICH RESULTED IN A REAR END COLLISION BECAUSE VEHICLE WAS GOING FASTER THAN THE SPEEDOMETER INDICATED. DIGITAL GAS GAUGE ALSO FAILED TO FUNCTION WHICH RESULTED IN VEHICLE RUNNING OUT OF GAS WHILE DRIVING ALTHOUGH THE GAUGE READ HALF OF TANK. THE CAUSE OF BOTH FAILURES WAS UNDETERMINED.*AK