Ive gotta ask you ess_three...
Which car is faster? Take it the tug boat puts more of a smile on your face?
Which is faster depends on who's driving it.
Anyone can jump into a mildly tweaked Mk6 GTI and get it cracking at a hell of a pace...it's just good straight from the showroom, and it'll forgive a lack of driving talent as the electronics sort things out.
If you are in the mood, and get keyed into it...I'd say the Mk3 would be quicker on a back road and faster round a track...but you have to learn how to get the best out of it.
The thing is, you can go silly quick in the Mk6, with a passenger, chatting away and listening to music.
In the Mk6 you buckle up, hold on, and enjoy 7300RPM as a soundtrack.
The Mk6 is a great daily driver. Real world as quick.
The Mk3 is a noisy, crude, bone shaking device...that just loves to be hammered...and makes you grin like a loony doing it.