The 8v will have a 2 inch bore, 16v 2.25 inch bore. Carb models and very early GTI had a different downpipe held on by clips with a manifold to match. If you want an 8v GTI exhaust, standard flows fairly well but make sure you get a decent brand like Bosal or Walker or even better, genuine if you can find one.
yeah bosal and walker seem to be good makes but ideally I would like an Ernst like the one that's on it. as they sound nice and seem to last pretty well. my other mk2 has a genuine vw centre box with 1998 stamped on it so that's done well
. genuine would be pricey but they seem to last a long,long time.