a mk2 is more involving and early mk3's did suffer from reliability probs but not anything to bad, parts for a mk3 maybe slightly more expensive i dont know. a mk2 8v is quicker than a mk3 8v, both are tidy cars and where the right badge tho. i would try and drive both see what you prefer.
black gti is yours an 8 or 16v? not for any reason just wondering, it looks quite tidy from your sig pic