I'd be leary of a salvage title with only dented/scratched doors like you state. In order to be salvaged..it usually indicates there was more damage than the car was worth, but someone bought the car from the insurance company because it was considered "totaled". Beware.
What my father has done for years is put a small tissue box on the dash and put the detector sandwiched under a layer of tissues inside the tissue box. I'll have to admit..it works great!
being 6'-5" tall..I had to lay the seat flat after releasing the glovebox door. So, it makes sense to me since I am lying on my back, on my head in the passenger floorboard area...lift means push...push means lift...