It will only go this far, and when I look on the other side, it appears larger than the square hole.

you need to take the wires off first (on the back) then it'll come out in a slight angle ...
Andy

This is very easy. The electrical connector spade is at the bottom of the switch. You can pull and angle it towards the inside of the car and remove it with the wire still in place. This helps as you might want to mark the position of the wires to reinstall. Or as Andy suggested, remove the speaker and fish up inside and pull the wires off and remove. Not much to it.

I got it out. Mine was stuck because the plastic was deformed at one of the contact points. Who has new ones?

I got mine at the local Porsche parts department.

One from a late model VW should fit, right down to the rubber seal