Touareg wheels
Centre bore is 84.1 mm I put 235 65 17 michelins on and everything clears. If you go bigger on tyres you may need to wind the lock stops out a bit
http://www.pxwheels.com/wheels/list.php?brand=Mercedes%20G%20Wagen
You would need to match the offset of wheel style No.7, which are the type that were fitted without wheel arch extensions.
http://www.rubicon-trail.com/G-Class/wheels/start.html
"...Valid for all Mercedes-Benz Gelaendewagen wheels: they have a 5/130 mm bolt circle (5 on 130 mm bolt pattern) , ball seats (very important), 84.1 mm (3.310") center bore (also very important), ET 63 mm on most stock wheels ...
The bolts for alloys are longer than those for steel wheels (as the wheel material is thicker).
All original G-Wagen wheels have round, radius-ed holes for the bolts. You will need to check your Touareg wheels to see whether they require bolts with a conical seat or a radius-ed (ball) seat. They need to be 45mm long for original alloys.
Radius-seat bolts:
These have conical seats: