A Mk1 can accept the former, but they tend to get used in a Throttle body setup as the overall height is too tall with the 16v plenum.
Quite a few Germans have done a KR conversion in a polo, it is quite possible, but you start getting into the argument that the polo is a lightweight car so we tend to stick to the short block engine as opposed to tall block not to mention the weight of the heavy golf engine, making it front end heavy, quite understeery etc, in a road format. It also would sit quite low so little ground clearance from the sump.
I did look into it on my old black racer about 5years ago now, even got a KR engine to test and put it on TBs, but nothing really came to anything as I wasn't going to get a salzmann subframe to convert it as I had a full wishbone setup already.
http://www.vwtuningsalzmann.de/SeitePolo1.htm
