i have just the standard type bought from halfrauds, the master cylinder transmits the braking force to your calipers at the end of the day- if it is worn you'll be getting a softer less efficient braking process i would have thought.
just my 2pence as i don't think the standard brakes are that bad in good order- the mk6 RS2k uses the same 260mm brakes with more power and weight and they work ok lol