Errm..rear led lights, black front xenons, central rear exhaust system and diffuser....even black wing mirrors, granted not the front LEDs/ bumper
there's not much else different to be honest...apart from your fav side skirts!!
I think you might be indulging in a fair bit of exaggeration with the above list of 'R' retro-fits.
I am truly surprised that there are some very stupid GTi owners who have reverted to this quite ugly centrally mounted twin exhaust feature of the 'R'. I dislike these as they look terribly out of place.
The reason the GTis exhausts are spread apart is to give the rear a semblance of width and prevent it looking like a fat bloated 'R' duck from the rear.
The Smoked Bi-Xenons: I am glad I did not purchase these as I far prefer the standard non- smoked Xenons of the GTi. The look more jewel-like.
The Black Door Mirrors: These are tasteless and are a sad 'one colour fits all feature' that is best avoided. They cheapen and chav-up the look of the 'R'.
I feel that the iconic GTi is the superior looking car.

Goodnight.
