Originally Posted by BadCon
I would drill the holes. Also, there are locating tabs on the spoiler which would need to be cut off if you don't want holes drilled. That said, look at the side profile of the car with the GT500 spoiler. It hangs far off the car from a pretty steep angle, that's a decent amount of force for tape alone.
^^ This ^^
I know a Mustang buddy that installed a newly painted spoiler (california special) with tape only. Blew off the car within a couple of hours. Scratched and gouged it all up. It may
have been because he did not prep the surface correctly, or did not use 3M automotive tape, or perhaps not enough tape (that stuff is industrial strength!).
But why chance it? Its a large piece to be only using tape. The factory used tape and
threaded fastners for a reason.