all you need to have is a L8 ecu from a 4x4 saff, make sure it has the relevant tps sensor, and a chip to run your spec.

the lambda wires to pin 2 of the ecu, feed the sensor with a live and earth from the wiper motor job done.

all in it is fantastic, engines will last longer, oil stays clean for longer no borewash etc... on a run i have seen 38mpg....but i was driving very very carefully, mixed driving i average at about 28-30mpg.