We just completed an '88 Carrera project with KW V3. I followed Joey Seely of Emotion Engineering's recipe based on notes I've taken from him over the years:
-Stock torsion bars, in your case I think upgrading to 1986 25mm rear bars.
-Stock sway bars with adjustable rear links, again upgrade to 1986 spec 22/21 sways.
Elephant also has a hollow adjustable rear sway bar that looks stock and is equivalent to the 21mm swaybar in its softest position. I'd love to try that. You'll probably need swaybar mount reinforcements if you're running sticky tires.
-Rubber spring plate and control arm bushings. We use Elephant
-Monoball trailing arm bushings
-Joey says monoball camber plates. We tried Tarett offset plates and WEVO monoballs, but they were both so clunky that we couldn't do it and ended up with stock. (One of my buddies has Elephant monoball conversion bushings in his 930 and is happy. We also have Elephant quick adjust camber plates in a 930 and they are quiet as well.)
-We used
Tarett's bump steer kit on turbo tie rods. (FYI, the steering rack spacers have the opposite effect with raised spindles!)