The 4Motion Technical Information is really scary, when you think VW can't even get the options right on their configurator when processing new orders without even getting oily fingers, how the hell they will manage to repair a 4motion is more than a bit concerning!
Anyway a bit late for concern , because we've ordered a new T6 4Motion with diff lock.
The thinking behind it was we do mostly wild camping and when driving off road to access remoter spots, not necessarily thinking that we're going to be mud plugging, it's really reassuring to think that you have all the options to get you out of wherever you might be getting yourself into. This gives you the confidence to explore that little bit further, but I must confess previously we have not needed the diff lock to get us out of where we've accessed, YET! although having a diff lock on SusiBus T5.
If you're having all the other bells and whistles I think a diff lock is worth considering for several reasons, you may want to visit Iceland, travel to the Alps in the winter, enhancing the resale value, or in our case just exploring that little bit further off road!