I know I should really...
There were some new patten ones on ebay made in Denmark but the guy has sold out... I may wait till he gets some more or may just go for new Mk3's after what you have said... I thought there would be a big difference in the weight of the MK3 Vs MK4 calipers... I also thought the MK4's being an alloy would be less likely to seize or corrode... Hence my thinking..
I sell second hand Porsche Calipers and have no issue with using them on my S2 but, they are I guess a different ball game to Stock VW calipers...
... I am not about to skimp on the brakes...
So buy new, not used 