Did my install of the filter and door yesterday. I found it a little more difficult than I thought, probably through my own fault to some extent. I burned my fingers by touching the hot knife to see if it was hot, and drew some blood on some sharp edge under the dash. Cutting the opening out went slow but OK with the hot knife, it does however leave a kind of jagged cut as it melts the plastic. That was not a problem though, as the filter slipped in with no trouble after you figure out the angles to insert it. If I were to do this again, I think I would just use a box knife with a new, sharp blade, and make multiple passes. That would leave a nicer cut.
The cover went on with no trouble either, it latched right on with no need for any force at all.
I did have to use a tie-wrap to hold the large cable out of the way and left it that way to make future filter swaps easy.
If you tie a piece of string around that little spring loaded cable, you can easily retrieve the end and hook it back to the glove box door after you are done. The '14s have the cable, earlier models may not.
Ran the blower at full speed and am getting plenty of air flow and no whistling or leak sounds around the new little door. If air flow were to be an issue in really hot weather, one could easily pull out the filter and be no worse off than it was before the mod.
Got this done just in time for pollen season. Can not imagine what my blower and ducts would look like with all the pollen we get around here.