Short version: Don't bother.
My wife bought me these for Christmas and out of the box they look great. Beautiful glossy genuine carbon fiber that looks like it'll fit great. They don't come with the trim tape pre-placed inside like others I've seen, but no big deal. The big deal is there's no way to get them in place and have them cover all of the old mirror cap. You'll always have gaps on one or more edges, and the bottom flares out too much to fit properly. With strong enough trim tape that would hold for a while, but don't count on it. The dimensions are off as if the mold they used was intended for a replacement mirror cap instead of for a product meant to go over the original cap. I tried fitting them directly to the mirror with the original cap removed and sure enough the overall size was better, but there's no way to attach them that way. The bottom still flares out too much and one of the sharp corners at the top of the mirror cap is too rounded on this item.
I'll be replacing these with 3M Scotchprint film sheet. I've used that before on my E46's interior trim and not only does it look great, but fitment is obviously not an issue since you trim it to fit yourself.
