I did this last weekend, after buying a couple off n8sby on here. Thanks!
It's a very easy mod, if slightly time consuming and at times fiddly. It took about an hour, including taking the pics. If you're thinking of upgrading, it'd be worth combining this with upgrading the interior lights to map lights/adding the sunglasses holder and/or auto-dimming rear-view mirror and/or parrot at the same time, as you have to remove all the same bits.
I'm sure most people on here could do this standing on their head, and may already have done that, just to prove the point! , but for the avoidance of doubt, here's a complete breakdown of how to complete the job.
First, a before shot and a close up of the two Torx T25 screws to remove from the visor, and the hole once the visor's removed.
Next, remove the retaining clips, shown with the plastic clip pulled out a little and then removed. Be careful not to lose the spring and plastic bit from inside it when you pull it off. Also, DON'T try to remove the metal clip in the roof until the headlining is down, as you could end up marking it.
Once you've removed both visors, it's time to remove the A-pillar trims. Prize the plastic lug out (easy to damage, so note the direction it moves - toward the windscreen) and just pull the trim away from the pillar.
Next remove both the grab handles, by pulling down, prizing-up the covers and removing the screws, then carefully pulling free. This step isn't essential but allows more of the headlining to be dropped, making the whole job a little easier.
Remove the blanking plate/sunglasses holder and ultrasonics modules (to give access to the retaining clips), unscrew the light cluster (3 x T20 screws) and remove the whole unit from the roof (use your fingers to reach in and release the four plastic spring clips). This photo is actually from when I upgraded to map lights as I forgot to take one this time round.
Now the roof lining should just drop down and you will (hopefully!) see several looms taped-up just behind the light console and to the left and right. The black wire on the left is my parrot mic. I'm guessing the plug you can see is for the auto-dimming mirror, which I don't have yet, but which would have been useful to do at the same time. If you don't have the looms, then you'll have to wire them yourself - it should be easy enough to take a feed from the lights console.
Now the lining is out of the way (mostly) it's a good time to remove the metal parts of the sun visors retaining clips. This is the fiddliest part of the whole thing - using a pair (or two!) of crocodile pliers, squeeze the prongs on either side together (2 on each side) and, with a bit of persuasion with a screwdriver, the fitting will eventually come out. You may need to bend the pins back into shape again afterwards.
The next three pics are taken from outside the car, showing the location of the looms on the inside. The looms are folded over on themselves, with the plugs nearest the light console and all taped down with that horrid sticky white fabric tape. First the driver's side all taped up and then released - do this very, VERY carefully and slowly to avoid damaging it. Also the passenger side.
You need to carefully release the looms nearly all the way back to the centre so that there is enough slack to allow them to go into the hole in the roof and pop out the next hole again in the right place to be plugged into the visors. Put a finger in the second hole as you push the loom through and you should be able to feel it 'arrive' and guide it out. Worth connecting them up and checking that they work at this point!
Now you can put everything back and, as usual, refitting is the reverse of removal! Apart from the visor retaining clips - once you've reassembled the module (see below pic nicked off eBay), just push it back into place (the right way up!).
You'll be left with the power wires hanging out of the holes in the roof. Just plug the visors in, pop the connectors into the holes and screw the visors in. Job done!
Now if someone could tell me the part number for the bulbs as one of mine is missing. Or does, perchance, someone (Kman247?) do a bright white LED replacement for a reasonable fee...?
Hope that helps someone!