My '03 350Z has a STILLEN Rear Valance (PN 1035018) that has started to detach from the rear bumper. The backup lights have also detached from the bumper after one of my neighbors backed into my car years ago. So, I'm planning on taking of the whole back end and was wondering what I should use to attach the rear body work?

It looks like 3M carries a number of different "Automotive attachment tapes". Is there a recommended tape to use for something likes this, or some other product I should be looking at?

 

The 3M tape should work. The problem is properly cleaning the back surface of the Stillen valance (and rear bumper) to have a perfectly clean surface for the adhesive to work.

 

If you can add a couple of discrete self tap screws, do so (with/under the tape) to avoid damaging cars behind you if/when the 3M tape fails.

And it will if it hits the road on a bump or pothole.

 

You could also try using some type of panel bonding adhesive if the double-sided tape doesn't work. As far as your rear turn signal housings being loose, it's likely that the impact caused the inside tabs to snap off on either the light housing itself or the inside of the rear bumper, but you'll know once you take it off.

Here's a good write up to remove the rear bumper: https://my350z.com/forum/body-interi...-pictures.html