My 135i is a staggeringly good bit of kit out of the box, proper Cayman S pace - obviously lacks the delicacy and feel of Pork (what has it?), but adds 2 more seats and stage 1 380BHP potential in a sublimely balanced chassis.
I've yet to get behind the wheel of a 1M, but if it's my car dialled up to 11, then it'll be superb.
As has been said, a Golf always will be at its best as a £25k hot hatch, straying too far up the price range puts it in a league it can't and shouldn't compete in.