FWIW, and u can see the pics in my gallery, its not for everyone but i didnt want to drill into the bumper. im probally going to go ahead and do it sometime since ive decided to purchase the truck (started out as a lease but we decided we wanted to keep it for sure).
i got stick on, no drill, backup sensors. it was 4 sensors and the control module, EZ hookup- wires to backup lamps. has tiny speaker that mounts inside (mine is routed up through the hole in the bottom of the cab and its actually tucked inside the plastic b pillar trim). its plenty loud to hear, and i put a switch on it to override it when i am hitched to the boat etc. cost me about 40 bucks shipped. well worth it for me. but again, since they do stick on, its not for everyone but lots of people havent noticed they arent stock.
ill save u the time, heres an older pic of them...see they dont look too bad....i think the drilled ones would look better...but i'll do that one of these days im sure