The upper links in the rear have different bushings between early and later axles. It's been some time since I did the swap but IIRC, you'll need the earlier bushings at the car body and the later ones at the axle. I would replace those bushings with new; they die pretty regularly (the lowers, anyway).
Inspect the panhard bar bushings; might be a good time to replace those.
Rear swaybar bushings go, too, but are $$$.
While on the topic, replace the front inner sways with poly (from sasab.com) and poly outer (from anywhere, but get black ones, not red, which tear more easily); cuts down on the lean nicely. Lube with anti-seize.
The e-brake systems are totally different between early and later -- I never finished mine, but it seems like people weld in the later style lever. If you have the time/inclination, you might be able to devise a pulley system to re-direct the original lever's pull back to the rear. It's a bit tough to explain but makes sense when you view both systems.
You'll need to drill a couple holes for the cables, but it's obvious when you look at your donor car how it all has to happen.
May as well bleed your clutch when you do this swap unless you know it to have been done recently.
Remove the small (14mm??) caps over the rear e-brake adjusters and spray some lubricant in there.
Oh, just remembered: you're going to need the brake lines from an 88-89 rear axle, as those years were non-ABS. Pretty sure your ABS donor lines won't work (single channel).
I assume you're going to put in some more front neg. camber. You can do this mo' easily by harvesting the shims from your donor. Stock spec is pos. or none. Get rid of some of the toe in, too.
@Snipes -- Brad does not post on forums any more but I think he's still building race cars. An acquaintance of mine in Seattle makes a variation of his spring set-up that's quieter on the road, better suited for street cars, not the racers Brad designed it for. He also builds a nice crank sensor bracket for Trionic conversions.
