Five hundred dollars for a wire harness. Bucks for an ECU, unless it's generic and the wire harnesses are wireless or show no wire to the back of the plug. The AB$ box. The hardware to mount it. The ABS hoses out to the front of the frame, and those parts to keep the hoses in place. The rear brake lines that run from the box to the back brake, so those take over the brake hoses of the regular hoses used.
Next bike might come standard with ABS if not many bikes gradually moving to the next standard tech move. So pass on the upgrade. It may cost a few thousand buy the time you're finished, and that could have gone to the next bike [upgrade].
Tormenting the motorcycling community one post at a time