I just did the thermostat replacement using the pelican diy and the video posted by Brigand253 and Athfar's tips. Thanks! I just now noticed there was a (short) second part to the video.
I'm sort of new to this wrenching business. I've changed the {oil, air, cabin, fuel} filters in my car as well as spark plugs and DSG fluid/filter. Those are all pretty easy compared to the thermostat. This job was an exercise in patience and putting things together since the 'diy' for this procedure isn't any detailed as the other diys I've followed. Anyhoo, here are a couple of tips in addition to the ones taken from the sources I already mentioned.
Tools that would be really nice to have:
1/4 torque wrench with a few sockets from 8-13mm.
3/8 torque wrench for the alternator and belt tensioner
an assortment of extensions for torque wrench/ratchet.
8mm open end/box wrench for the alternator harness wiring nut.
Of course, you'll need a 5mm triple square bit.
Tips:
Contrary to the pelican diy, you do not need to take off the driver side lower well wheel panel.
Draining the coolant:
I'd recommend ignoring the pelican guide on this one and use the video to get a better location to drain the coolant. Or follow this diy:
http://myfastgti.com/volkswagen/threads/17420-Coolant-Flush-DIY
For putting the alternator back:
In order to recess the threaded brass mounting disk on the alternator, I used an 18mm socket and a C-clamp to push the disk in. Alternatively, you can follow the procedure from the second video and use a socket/washer/bolt/rachet to pull it out.
Remember how you pulled out the alternator because that is how it will have to go back in. IIRC, basically as you're dropping it back into place, the ear should be facing you as you move it into the in cavity where the mounting bracket is and rotate counterclockwise.
Refilling the coolant:
This might be obvious for some but it wasn't for me... I tried taking a shortcut that didn't work and made a big mess. Always gradually fill the fluid and keep between min and max. If you go way over max like I did, the excess will leak through a hole in the passenger side plastic undercover. It would also be best to premix your coolant to 50/50 or whatever before introducing it to your cooling system.