I've got pi ----- sed off re-sticking mirrors back onto the windscreen with double side tape , even the heavy duty stuff fails eventually . With careful use of ducktape and a short piece of wood from tunnell to under the mirror , I put it on with black Sikaflex but let it dry on the mirror part for 2 hours first (not quite so fluid then) , to help stop it from sliding around from the position. Twenty four hours and it's solid --- brilliant stuff
I've used plenty of it in the building of the car and again fixing the new tow strap velcro onto the front valence.
It's not important for competition events but useful on trackdays or testing --- the side mirrors don't show much on mine until they're nearly on top of you.