Probably most important is the self adhesive on the back. Some of the currently available "emblem tape" is a little to thick for my tastes and it shows too much of itself at the edges of the emblem. If I were to do it, I would slightly counter sink the head of a flat head machine screw and epoxy them onto the emblem backside. A nice flush fit will go a long way to a clean near factory look. But of course if you want them removable without any trace, that's not the way to go.