I purchased the Hotheads. They are attached with doublesided tape. The inserts themselves are so tight, that they will push themselves out if not PERFECTLY centered.
One of the panels was ever so slightly warped. When perfectly installed, it pushes out on all sides, and pops loose. I've doubled up the tape, which in turn drops them down ever so slightly. You can't tell. They fit much better this way. Plus, I don't want these things popping out in my lap when I've driving.
They do seem to be ever so slightly quieter, and look really nice. I did the black ones.
I did contact them about the fitment, and was told it was impossible for them to be too large.