I've driven a MK5 GTI and an R32.
GTI "feels" fast IMO, it's not if you time it but just because the turbo boost feels fast.
The R32 is more luxury and lazy "do I have to do this" but while actually getting to 60 etc very fast.
You could say that the R32 is heavier and if you kept the GTI on boost well round corners then you could think it's faster I'd agree because it feels more "yobbish" but I'm definately sure the R32 would do it much quicker.
It's hard to describe. The GTI is quick and feels very quick throwing it about but that's because the R32 is so refined and luxury IMO.
GTI is much more boy racer to me then the R32 and the R32 is a lovely car to drive, reminds me of the M5. Neither FELT as fast as I'd thought, until you looked at the speedo.