I've pondered this topic greatly, and I think you should sack it and get a proper tomcat 
Got one on our drive if you can trailor

I've had 2x16v and 1x8v, 3xR5 turbos and my son (he's a VW technician) currently has a T16 Tomcat which is quick, looks great but rarely goes for more than a week without something breaking, spares are very difficult & expensive to come by, keep away unless you have very deep pockets, a garage, RAC membership, loads of spare time, are good with spanners and you can walk/bus to work.
R5 turbos, much quicker off the mark and more fun than just about anything i've driven but top speed no better than 16v, mine were all newish so no probs, been looking at getting one again but good unbutchered ones are rare.
16v, good but a bit frantic to get moving quickly IMO.
8v, feels more responsive & less gear changing.
As said, both GTIs are good but these days solid bodywork is probably the best reason to choose.
My choice would be an 8v day to day on the road, but thats probably due to my advancing years.
