So, the later mk2 has a bodykit and bigger spoiler - and the earlier version has no kit and a smaller spoiler The first question would be why VW made the change - purely cosmetic or for aerodynamics? What I've noticed is that the (very few) track Sciroccos that I've seen have kept the kit and spoiler, rather than saving 15-20kg in weight. Again, I wonder why they kept the kit - cosmetics or aero? .
The beards'll claim it's something to do with aerodynamics but having driven both I couldn't tell any difference. Have you? Saying that, I've never raced one.
On the road, I doubt you`d tell and difference whatsoever. On the track, it`d probably be minimal too, but better.
Up to the legal limit there is certainly no difference. My experiences beyond that can't really compare as one car was standard bar Koni/Eibach and the other was stripped, caged,had mahoosive ARBs and was consequently bouncy as bananas.