you're gonna have fun and games fitting those mk4 rims to a mk3... i tried to do exactly the same thing
if your fitting experience is anything like mine the fronts will go on no problem but the back will hindered by the hub split pin cover...
you will need to prise this cover off (it will be full of grease - keep the hub cover for when you decide that you don't like the rims anymore) and then use a 3mm spacer so that you can pop your centre caps in!

this is what they look like fitted...


i have a set of these spare if anyone wants to make me an offer (pm me)

oh, and pleeeeeease fix your caps lock button!
