This left the job of installing the spoiler and camera. After much concern and 3 times thinking it over I decided it was time to drill holes in an otherwise perfectly good trunk. I took some thin cardboard, taped it to the trunk in the general areas where the 5 holes would go, and began measuring, eyeballing, measuring more, eyeballing even more, measuring one last time, and finally pressed indentations into the cardboard where the holes would need to be drilled.After drilling the four 1/4" holes and the one 1" hole for the camera wiring, I put a circle of automotive silicone glue (for waterproofing) around each hole and proceeded to tighten the four nuts and ensure the 1" rubber waterproof grommet was in place and sealed again with the silicone. Replaced the trunk lid liner and there you go. Backup camera installed.
This is just an update to let anyone who's interested know that my backup camera factory install worked out pretty good. I wanted to keep the car as stock as possible and after much research decided to buy a spoiler w/camera off of ebay. It was $140. I did a quick test to see if the trunk lid camera plug would just send a signal to the 8" nav screen. Of course it didn't so I continued to educate myself in the workings of backup cameras for mustangs and discovered that there is a program available from 4DTech for $150 that tells the mustang computer there is a camera installed. So I took a chance and fortunately 4DTech is a company that seems to know what they're doing. The camera worked.