Sockets came, not had time to do anything with them yet, but I think it's promising.
I'm also going for the w5w/t10 fillament bulb inners. Do I need 5watt or 3watt W5W/T10 bulbs? And 'normal' or 'red' ones?
I bought 4 small t10 sockets (about the same as yours). I'm going to solder the wiring onto the sockets (onto the little contact-lips you see on the sockets).
They are 'twist-and-lock' sockets, so I only have to drill 12mm holes and make two notches in each hole with a dremel.
Tried a experimental setup (drilled a 12mm hole in a plastic plate and made two notches in the hole) and the twist and lock mechanism works perfect!
The sockets are only 8mm's high, so guess they will fit in the small space behing the inner tail lights (if not, I can easily shave off a little of the plastic holder/gripe)
Sockets:
I've removed the rear lid trim, but
how to route the wiring from the inner tail lights to the license plate lights? (So I can connect them and disable the cold startup diagnostics with vagcom for the licenseplate lamps)
Is there a how-to for the wiring?