I just installed a backup sensor kit from www.sensortech.com. It is a radar type device that requires no drilling holes for sensors into the bumper. Relatively easy to install. They give you heavy duty velcro straps. I did not have to remove the bumper. There is just enough access to slide your hand up behind the bumper and over the steel guard to install the device. I removed two of the clip pins holding the bumper underneath to give me a little more room for my hands. A tip for removing these pins - put your finger on the washer piece on the outer ridge and pry the center pin up with a flat blade screwdriver. Do not try to pry up under the plastic washer as they will break. Make sure the center pin is still popped out when re-inserting. The device is about 2 inches by 4 inches. You attach the velcro to the inside back of the plastic bumper (above the steel guard) and the other piece to the device. Wiggle it into position. The wiring is simple, finding the access hole took some time -there is one on the driver side and you will need to remove the back panel (in the trunk) to get at it, but it's only held on by two screws and some plastic tags. Once the wires are through you connect to the backup light - easy too - they are up under the trunk hood - red wire positive - white wire negative. The kit includes a small indicator light which also sounds the beeper. I installed it inside one of the air slots (vent for the battery pack) and routed the wire under the rear deck panel and into the trunk. This way, I can see it in my rear view mirror. So far, so good, very sensitive to movement (i.e., a child, or something). The only drawback was the price - 300 bucks. Hopefully it was worth it, will let you know.