I'd played with the idea of a brand new mk7 GTI, R or Rocco of some sort, and there's many things to tempt me in. Like being able to choose the exact spec I want from the start, warranty cover, no MOT for 3 years, and many other smaller positives.
But the final outlay for going to a brand new car is a lot of money. Money I can spend making my mk5 the exact spec car I want. This has the added bonus of being able to have things that maybe aren't available on a new mk7 GTI (for example, Recaro bucket seats). I can effectively re-build my mk5 GTI, with more power and comforts/toys and have change left from what I would have to pay to own a mk7 GTI/R or something.