FWIW, betalink is pretty much a permanent solution, that spoiler ain't coming off in one piece (or if it does, your trunk will need work). Probably not a big deal for most, but if you ever envision yourself taking it off eventually (to repaint trunk, or replace with a CF trunk, or sell, or replace with another type, or whatever reason), 3M double sided automotive tape is better IMO.
If theft if your concern, bottom line is if someone has decided to steal it and take it off, Betalink won't stop them. It'll just leave you worse off to clean up after the mess (where chances are you need both a spoiler and a trunk
).
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2011 BMW E82 1///M: AW, all options; Renntech, Akrapovic, Forge, P3, RevoZ CF bits, many mods
1988 BMW E30 M3: Hennarot, S14, stock
2018 Porsche 991.2 GT3: PtS, CXX, LWBS, PCCB
1998 Porsche 993 C4S: Zenith Blue, last aircooled widebody, Bilstein PSS10, Fister II + Fabspeed exhaust
2008 Audi B7 RS 4: Sprint Blue, Audi Exclusive Euro Bucket Interior, Premium+Titanium, many mods