Sixth mod: installed a permanent remote control for the gate motor.
My gate works with two generations of remote controls. The new model is more modern and takes a 3V battery. The old generation, however, used to take a 12V lithium battery. So nine years ago, when I installed the gate motor, I figured I could connect it directly to a 12V supply in the car and install a button in the car, so I have it always at hand and never have to worry about replacing the battery. I did that in my first Mondeo, then transferred it to my second Mondeo, and now I've transferred it to the Mustang.
The best place, all things considered, was on the plastic trim that surrounds the driver's seat buttons.
I'm very pleased with the result. It's discreet and very easy and comfortable to reach.
The remote control is hidden behind that plastic trim. Try as I might, I can't take a picture showing the remote control itself - it's well hidden behind those metal brackets, though it can be seen from a certain angle if you know exactly where to look. Follow the wires from the button and you'll get a rough idea where it is.
The power for the remote control comes from the connector that goes into the command panel of the seat, which is right there, directly behind the command panel. A couple of minutes with a multimeter told me which pins to use.
As a bonus, this connection is permanently on, so I can use the remote control at any time, engine on or off.