There's a guide on how to do the later model shifter change somewhere out there and the cable interfaces are different from what I recall. At the end of the day I figured it just seemed like too much of a headf**k for what the perceived benefit would be.
If you've addressed all the bushings in the shifter assembly and cables and the shift feel is still not satisfactory, then you might have to take a look at your gearbox internals as it could be a warning sign things are on the way out inside the casing.
Like I said - packing the springs for the de-tent balls made a notable improvement to the shift feel and is something you can do with the gearbox in the car (the 3x bolts for the springs/ball-bearings are accessible from the front of the gearbox casing - just don't let the springs shoot out when you take the bolts out!)