Before - 23.5mm T-Bars. Rear bumper height was 44mm higher than front. Supposed to be approximately equal.
After - 26mm T-Bars, poly-graphite spring plate bushings, 95A durometer polyurethane swing arm and tube mount bushings. Rear bumper height is now 3mm higher than rear. Note that as rear bumper height drops, the front goes up a little as well. Set rear camber to -1.45deg and thrust to 1mm total toe-in.
This was actually not at all hard to do, however it is extremely time consuming to research, make many detailed "before" measurements, disassemble, sweep floor, inspect and clean parts, reassemble, sweep floor, align, take many more detailed measurements, and finally bleed brakes. I figure I spent at least 40H start to finish, after having all the parts, tools, and new hardware ready and on hand. Remember that this was my first time and I was doing this part time because I was on vacation, so YMMV. Oh - and I got the indexing spot on THE FIRST TIME thanks to the "spread sheet" from the 944-spec (dot) org web site.
Test drive was at night on my favorite twisty road (Indian Crest Drive) and kept being interrupted by pesky deer crossing the road... Wow. Why the hell did I wait so long to do this?
Surprisingly, both upper mounts are in almost new condition considering they are 30 years old.
It is now clearly evident that I have to address front control arm/tie rod geometry correction - rear is MUCH flatter but front still rolls around tight corners. Overall it is now flat on high speed big wide sweeping turns (i.e.: interstate interchange ramps). My entire suspension is now on poly (even the front strut mounts, but that is a whole new thread for later).