I remember on the Mk6's test drive a 12 year old noob and his mate in a old mk4 gti was inch's off my bumber for ages, then even pulled out into incoming traffic and whyen cutting back in, almost went into the front side of the test drive car! Not sure what it proved - that he was dumb driver?
Also think it depends on where you're driving and if it's rush hour. IMO Manchester is worst with everyone seems highly aggressive - cut you up\ drive through red, way worse than London. On the hand, each time I've been to Leeds or Liverpool, the drivers there seem to be far more chilled out and considerate, just what I've found).
Regarding cars in the current GTI I never seem to have problems, but I've also got a Corsa for a short while, and oddly I've noticed I always seem to get tail gated even in a 30 zone in the corsa, noticed it way way more than the Golf. Even when either car is driven at the same speeds about town or on the motorway.
But...... I know someone who has an R8 who finds they get tailgated by Golf GTI's all the time. I don't understand that, why bother as R8 is way faster than them, and if the numpty's crash into the back of an R8 (a tailgating GTI has no chance of stopping against an R8 doing an emergency stop) - their insurance bill will cost a mint!