The Gen III’s have quite a different design to the II’s. At least according to Arnott. They are not only longer allowing more travel (with longer shocks).
But the biggest advantage is on road. The Gen III’s unlike the Gen II’s essentially run the other way round. They are softer when extended and stiffer when lowered.
The Gen II like the Dunlop, BritPart or OEM setup is soft for motorway lowered height and stiff (maximum inflation) for extended ride height off road. Which is essentially the completely wrong thing you want for each scenario.
I believe the Gen III’s work very similar to the struts on the L322 and D3.
There is no off road setting on the P38 only a wade setting. You need longer shocks and modified sensor rods with gen 3. Nearest thing mine ever gets to off road is mildly moist grass. Mind you my drive is a challenge at times. Steep, twisty and bumpy. Even going over speed humps in wade is uncomfortable. It's a road car with some off road capability not a cross country vehicle suitable for roads. Lots forget that.