Raf_far.... Where hawe u heard this?? (I heard that because it is an AWD it is normal for the tires to wear out faster on the outside.) There is a big differens in awd and awd... A american 4wd with 100% locked front and rear axel wants to go strait when stering sharp..Like a truck with diffbrake on(100% at right and left tire).. When stearing it's chewing rubber and cost alot of fuel... But this is no problem with a outy due to its viscoclutch betwen front and rear axle.. On a outy there is 2 things that will wear out the front tires...1.. The all the time weight from the engine and 2.. Using the brakes .. +70% of brake energy is at the front axel..
This is the only thing that is NORMAL wear.. Anything else is unnormal and could be fixed...
http://www.google.com/search?q=camber+caster Plenty to read there.....
But thats not the only thing that can effect tires from wearing out... Sometimes the problem is between the stearingwheel and driwer seat.... Or just caused by hawing to low pressure in tires... Iam close to 40 psi 3,8 bar and moastly alone or with one pax.. And after 25000 km i can measure som diff at front inside wear propably due to fast cornering at citydrive... But this wear is like a fart in space..Nothing that could be seen without a instrument... And next summer i use front tires at rear axle to keep the diff in zize as low as possible..