I believe this should work for all 90s, but I have only done work on my Coupe Quattro.
When I bought my '91 CQ the shifter was all over the place. I had my cousin move the shifter around as I was under the car watching the shift bushing, but it didn't seem like that was causing the majority of the slop I was seeing. When I was driving around without the console on I could watch the ball coming out of the socket and also noticed that the "seal" and what not was not in place.
I picked up a shifter ball socket from a "1980 Rabbit" as was suggested here. It looked a lot like the 034 motorsports short throw in the pictures I could get my hands on, so I crossed my fingers and hoped it would be usable. It was only $30 from Hasley Imports in Portland, so I wasn't out too much money if it didn't work out.
Since I was replacing bulbs throughout the console I had removed it, but this could be done by only removing the shift boot. That can be done by removing the trim plate just ahead of the parking brake and removing the one phillips screw that can be seen in there. That releases the shift boot from the console. No pictures of that right now, sorry. I will try to think to add it in the future. The shift knob screws off. Once that is done there is a rubber grommet on top of everything to remove. Below that is a spring clip (get a pair of spring clip pliers), the reverse lockout spring and the collar that holds the spring in place. Remove all of those before moving on. This part I have found covered elsewhere, so if you want more information or pictures search around or ask me some questions. It wouldn't take much for me to go take some quick pictures and post them up at another time.
The shifter looks similar to this before disassembly. The ball in the middle of mine was coming out and causing most of the slop. Underneath the two nuts are a pair of spring plates and a pair of crescent (half moon) shaped castings that give the nut and spring a flat surface to bolt to. Keep the crescents and toss the rest except the nuts. Once everything else is removed put the crescents back over the studs. These will give the ball socket plate a flat spot to mount against.
PB040008 by TheHarley, on Flickr
The first test fit of the ball socket showed me that the slots were not in the correct position, but could be easily enlarged to accomodate the smaller bolt pattern. I enlarged the slots toward thes the ball socket in the middle. I referenced the picture of the 034 motorsports short throw and it looks like they did something similar. I used the original nuts from the shifter since they had a wider shoulder and then put the new pair that came with the ball socket on top to lock them in place. You could use a locking washer or thread lock instead, I'm sure.
PB040007 by TheHarley, on Flickr
PB040009 by TheHarley, on Flickr
Next I test fit the stock reverse lockout spring and spring collar. The spring fit fine, but the collar was too long to use with the new ball socket, so I shortened it. The collar has several steps in it and I cut the bottom step off as shown in the picture I roughly drew up in paint. Fit perfect after that and I was able to get the spring clip back on the shift lever.
Shift Spring Collar by TheHarley, on Flickr
PB040010 by TheHarley, on Flickr
PB040011 by TheHarley, on Flickr
Now just need to put the rubber grommet, shift boot, and shift knob back on.
I'm personally really happy with the results. I obviously no longer have my shifter coming apart. There is still some slop side to side, but it shifts really well and I still have the reverse lockout feature. Whenever I get around to ordering bushings for my rear differential from 034motorsports I will be picking up a shifter bushing for the linkage under the car too to see if that fixes the rest of the slop I have left. I do actually believe this shortens the throw too. The pivot point of the shifter was moved up with the rabbit ball socket, so theoretically the shifter has to move a shorter distance in my hand to change gears. I didn't drive it very much with the old shifter, so I don't feel I can verify this with experience. I do like the feel of shifts much better than before. It is very solid feel front to back, but that is at least partly from the replacement of the socket.
Drop any questions you have here and I will do my best to answer them.