UPDATE:
I will do this for the brz/frs community. Alot of people myself included have fears of wings flying off. Well, I've collected some data for everyone.
First with videos: [ame="https://www.youtube.com/watch?v=U2vbR34jBzk"]3M VHB adhesive demonstration holds up man -- Another Geek Moment - YouTube[/ame]
There are other videos. Double sided tape also used to hold on panels on skyscrapers also.
Now with other car forums people have used double sided for spoilers/roof spoilers and had no issues
ClubLexus owners:
http://www.clublexus.com/forums/gs-s...-spoilers.html
BMW M3 owners:
http://www.m3post.com/forums/showthread.php?t=651870
And, for my own experience. I didn't use alcohol to clean the surface, nor did I use the 3M tape primer. The spoiler is up on the right and left side a little, air can get under it. I may need to do it again, but it's on there. I put a decent amount of force down on it and it didn't budge. I need to take it on the highway and see how the tape holds up to snow, hot days etc..