The best tyres on the front or rear axle?

moin moin, somehow I never manage to drive down all 4 pirelli 6000 evenly. now two new ones are due for my ship w220, 430 k, 2-matic (:-). where would they ideally get there, front or rear? (take note of the running direction etc. makes the tyre service itself). I have heard from two different friendly just the two different opinions, so I put it here to the opinion statement. so long