My 01 has an aftermarket sunroof (actually moonroof) and gets way crazy wind noise; I also dont drive slow...
So I picked up a deflector from a yard. Just dont know how to mount it
Looks like most aftermarket ones just use adhesive.
That said, recommendations? Double sided tape? If so, what brand/product?

 

3m double sided. Same stuff for a front deflector.

 

Seems to be a lot of 3M and other double sided tape out there. Most reviews Ive seen say they dont stick at all on multiple surfaces... How's that going to hold up at 80mph?
Do you have a specific one in mind?

 

Try 3M 06384 Automotive Acrylic Plus Attachment Tape.

Clean both surfaces well, and let dry. Wax and grease remover, or even Dawn dish soap and warm water shoul do. Once dry, go over both with 99% rubbing alcohol or 3m (4298 or 6396) adhesive promoter wipes. I pull the backing off just enough to leave a pull tab. Position the part and pull the tab as you go. Apply a little pressure to help the tape conform to any surface irregularities. It should hold indefinitely. I installed window gaurds on the Mustang years ago, and they are still holding.

 

Forgot to add, avoid hitting the tape with a powerwasher if possible. Shouldnt be much of an issue, but its still something to watch.

 

Double sided tape lasted two days before it started coming up

 

It happens. What brand tape? Was it for automotive use? Were both surfaces (paint and deflector) prepped properly? An adhesion promotor might help (ive never used that stuff tho) if you still have problems with it. Just to be sure, check the deflector and roof for any warpage where the two meet. You need full contact between the paint and deflector. If you can clamp it down a little, that tedns to help. Also, low humidity and atleast 70* out should be perfect.