I have just ordered a set of 16" steel wheels and with 205/55/16 wheels, you can get either the 6J or 6.5J, both will fit onto the standard GTI or GTD.
I'm based in Germany and we are required to get the correct tyres for the road conditions, in all a full set with Hankook icept rs tyres cost €418 including fitting.
Interestingly I could have had a set of 18" winter tyres fitted to the OEM rims, for €386 but decided against it due to the amount of snow we usually get. Plus the rims would get rather pitted in the winter, I will post some fots once fitted at the end of the week.