Dude, whats this action all about?
You start with aligning the spoiler at the trunk w/o tape and other helpers.
If you encounter an improper fitting caused by large gaps you couldnt fix that with additional double or triple layered tape. In that case I would return the spoiler and thats it.
The normal way to install is put the 3M double sided tape first onto the spoiler, into the middle section I had used parallel stripes to cover more of the surface. Then place your spoiler again with covered adhesive strips against the trunk and make a last check. If its fine, remove the cover strips and install that thing. I had started to place the spoiler at the top touching points of the trunk, then make your way downwards until it is resting completely onto the trunk. To keep the pressing force up, I had placed additional some painters tape over the spoiler and the trunk at five places over the whole spoiler and let it rest for one night.
Next day removed and cleaned, worked fine for me. Spoiler had withstanded speeds up to 250kp/h and Im pretty sure, you into the US would never achieve this speed aside of tracks
