wiring is like hell. a good friend and me would do that. at the moment he is searching for some pins (funktions) what are not in s-chassis and searching for what they doing.
but....abs is no problem.
take the gtr loom, cut it off and remove all wires from the abs. 1-2 gos to ecu, the other goes to the sensor and the conecting pint at the front. all wires at this connector can be removed. there ars 6x thick wires, thats + from the injectors. in s15 they goes to the inside of the car.
the only things we dont remove from the s15 harness is, wiper engine, abs sensor (left wheel), the connector for the servo pressure, abs (complete). if i´m right now all other wires can be cuttet out.
i have now 6 weeks for finishing the car, so, may be i have some more inforations in a few weeks.