Hi,
I have a 130 big cab 300 auto and it is the best thing I have ever done. It used a new Disco box and was fitted by Bruce Davis at Annangrove in Syd--everyone who drives this car loves it and it has a beaut center console for the shifter-also Disco. There were no issues fitting it but make sure you do have a second transmission oil cooler as initially we only had a small one near the bull bar/bash plate and saw the transmission show 150 degrees in Vic High Country with a heavy slide on on board so then added a larger Davis Craig fan cooled cooler behind the cab just in front of/below the tray and it now runs 75 degrees which is about correct temp for these autos. the car now is much quicker off the mark in traffic, and we did fit a 200 tdi manifold which moves the turbo position for a bit more go, it hits top at 78kph and returns about 12lts/100. We do a lot of towing and no problems at all--best Defender as we hate manuals in traffic.