I recently installed the power steering kit, one of the best mods to date. The car is much more drivable now, and have no issues at highway speeds. I ended up using the GPS sensor instead of the speedo potentiometer that came with the kit.
Had no issues with the fitment on my 260z (uses the same unit as the 280z), it lined up perfectly in the location of the manual rack. As for the tach wire, I made a splice and attached it to the red/black wire on the tach itself. The signal is basically used to tell the unit when to turn off after the car has been turned off, so it doesn't dr