I did this mod years ago on 6.9 ford diesel and converted the serp to the vbelt pullies on the truck and it worked out.
I don't have ac or power steering on my rabbit and was looking to upgrade over 90 amp purely for the stereo.
I am not smart enough to know if speed that they turn and size of vw's pulley vs. original design might play into anything or if the load might somehow mess with my engine and put too much stress on it?
It looks like I could make it work, seems like the cheapest and easiest route for me to upgrade.