I have the Mk 2 and now run in auto all the time. Initially I tried to spot MPG differences between 2wd and auto but didn't find any.
I think** the drive is proportioned front/back in normal driving and so probably tyre wear is evened up to some extent, esp when towing.
** When pulling away (normally, not fast) from a driveway that's loose-surfaced with front tyres on tarmac and rear tyres on the loose stuff the rears seem to scrabble slightly, so it doesn't seem necessary for the front tyres to slip for some drive to go to the rears.
Bry