I understand there are two basic types of three-wire sensors.  One
has two white wires and one black wire, the other has three different
color wires.  

There are many styles of plugs on them, none of which are right for the 
VW.  Any of the two-white-wire ones are fine.  Try asking for a Ford
Taurus 1987.  Something like that.  Or a 1990 Mustang.  You have to cut
the plug off your old one, and off the new one, and swap the plugs.  Be
sure to do this far from the sensor and *solder* the connections.

malcolm