Well, the soldering is not exactly a body kind of job. More like an AV installer. A good stereo shop could do it.
If you do it like I did, you'll be able to remove it fairly easily. Keep the dummy switch you take out of the panel.
The targa switch has two sets of contacts, one for open, one for close. You can use them for the two switches on your opener. That is exactly what I did.
You need to order:
996 Targa switch
Switch connector body
Switch connector contacts (6 or more)
You'll also need some wire to install it and some vampire taps to get power from the phone harness or some other harness (radio, for example) in the car, and to hook up the lighting for the switch.
Open up the garage door opener and find where the battery connects. If the battery is 12 volts you are in good shape. If not, you'll need some kind of a regulator to drop the car's 12V down to the battery voltage for your opener. Assuming 12V, solder two wires to the wherever the + and - of the battery connect. These two wires will be connected to power in some harness in the car using vampire taps.
Find the contacts for the two switches. There should be one contact on each switch connected together and then to somewhere else. Solder one wire to the junction of the two switch contacts. Solder a wire to each of the other two switch contacts. These three wires connect to the switch. They'll be crimped into three contacts, and inserted into the proper locations in the connector body.
Take another couple of pieces of wire and crimp them into some contacts. These will be connected to the lighting wires on another switch using two more vampire taps.
To install it, pick where you want it, left or right. I put mine on the left side of the dash center console. Grab the panel by the edges and just pull it straight out. Pop out the dummy switch and pop in the targa switch. Push the switch contacts into the connector body (in the proper locations) until they click. Push the connector onto the switch and hook up the power and lighting wires to the car. Wrap the remote in bubble wrap to keep it quiet and put it into the recess behind the panel. Mine works fine from there, no need to try to get it in the bumper or somewhere else.
I think I took some pictures of my setup. I'll try to find them and send them to you. PM me your e-mail address. I'll try to find my information on the switch contacts and wiring and send it to you along with the pictures.
It's not as hard as it sounds.
Al