MO means Mercedes Only. i know that using Porsche tyres on cars that aren't Porsches does funny things to the handling but this is something i've read in one of T_T's posts so if he's given it the thumbs up then maybe it's not an issue. however i'd imagine that running Merc tyres on your VAG car would not make your insurance company very happy if heaven forbid you were involved in a smash.
one to be avoided imho.