After freaking out about cluster wiring for a month or so, I decided to pull my B4 cluster and see if I could even fit it in my EuroVan, as everyone says they don't fit in 2000+ models.
Well, they do. I put it in the dash and the fastener holes lined up perfectly. I think the only modification would be to get an earlier cluster surround. I popped my surround on, and with the steering column cover, there is just a small gap at the bottom of the cluster. Not a huge deal.
The other thing to consider is keeping the interior lighting scheme consistent. The B4 has the "green" scheme while the MK4 has "blue/red". I personally prefer the look of the B4 cluster, so I'm sticking with it.
I hope this helps 2000+ owners!