I just can't live with the fact that it doesn't matter how thin the tape is you can always see a slight gap. And I'm not new to this. I use tape on the splitters and the diffuser but not on the spoiler. What I do is grab a medical syringe cut the plastic tip off and use it to lay the glue nice and thin. Once you press on it it'll spread and practically no or very little comes out. Comes out great.
Just removed one I applied to my E90 using my technique and came off pretty easy with a string, sawing thru the betalink.
FYI betalink doesn't get rock solid it turns into a hard rubber when dry