Yes, I added backup sensors to my 99 Quest. I bought the Autopage BPS-4 kit from Sonicelectronix.com. I have been using them for over five years now and they are working perfect. Use the extra angle piece for each sensor to aim them up to minimize false alarms. These are sensitive sensors and the van is kind of low. They might beep while backing out of an incline driveway. As for the position in the bumper cover, I happend to find the right position by luck. The real metal bumper in under the bumber cover. It has a gap where the sensors will fit perfectly. If you don’t get the right spot, it would be nearly impossible to open a hole to the metal bumper. And, yes, you have to take the bumper cover out and re-install it. Run the wires to the rear left side of the van where there is some other wiring already. You will install the control unit in there. The rear right does not have space due to the rear A/C unit. The wire for the buzzer is long enought for running the buzzer to the front under the steering wheel. Run the wire under the carpet on the left side of the van. If you provide me your e-mail, I can send you some pictures of my sensors.