does anyone know f the steering coupler bushing can be replaced by just loosening the 4 bolts on it, or does the column need to be removed?

I definitely did not remove my column. But I did have to remove the bolts that attach it to the rack if I recall. Just take your time and carefully remove what you need to. You will do a great job!

Mark the two shafts so you line it back up correctly as you may end up turning the wheel to get at all the bolts.

This swap can be done without removing the shaft or the pinch bolt from the steering rack. It is a bit daunting to get the bolts out and back in again but can be done. I think the trick is not to remove the bolts all the way that bump into the u-joint, just slide them up enough to get the coupler out.

The cheapest and most noticable improvement I have ever made to any of the Z's I have done. It's easy all work is done at the "doughnut"only. Lube up the 4 bolts /nuts. Of Course things are marked B4. Then as with any old threads, Crack it, Tighen it. spray it.wipe it . run it out until it it just seems too much pressure. UH.. Lather rinse repeat..