I don't use anything but V-Power and Momentum-99 in my car. That's what VW recommend for the 2.0T. You can use a minimum grade of 95RON but that's not really meant to be regular. i doubt it does any harm tho.
In the fuel flap on my Gti it says use 98RON or above.
I stick to tesco 99 normally but been using V power for last few fill ups, i seem to be getting better mpg and seems to pull better.
Funny that coz mine says 95ron
All GTI's I know say 95/98Ron with the 98 being bigger and bolder indicating that it is the preferred fuel of the 2 to have the car running as best it can but 95 is still fine to use