Drove both GTI and GTD and went for the D. The GTI is the star on performance but where am I to use it. I drive 28kms each way to work and the rural highway section has been reduced to 90 km limit (blackspot). I decided that if I was going to be responsible for giving birth to another vehicle on the planet that it might as well chew less rather than more fuel as the performance is more than enough for me.
After driving the the German autobahns I now understand why fast cars are made, but we do not have the roads like that. Before that experience I had real reservations about cars that did more than twice the speed limit, what's the point.
Comments about an extra 1.8 litres per 100 for the GTI as trivial do not add up. Round that up to 2, say the GTD gets 6 l/100, that is a 33% additional fuel for the GTI each time you fill up. If you have pushed the GTI it would be 50% more and if you did not push it, then you might as well have bought the D anyway.
Now having got that out of my system, I can still see why the GTI is the icon and why the golf is what it is. It's just me, I just don't need the top end, I need the torque, and cool.