it could take a while to do but the rs turbo runs a KE jetronic system
it is very similar to the K jetronic which has no ecu.

you can map a KE system because the metering valve has and extra unit attached called a pressure actuator that is ecu controled to modify fuel mixtures across the range, the k jetronic metering valve doesnt
and the ignition sysem also has a ecu to change the ignition map.

thats as simple as it gets.