DrD,
I have the old Ranchos with 5 settings, and once I let all the air out, the shocks are real soft. So much so that i get body roll - but once I hit ruts, that's a different story. And on undulating roads, the short wheel-base Sami tends to yo-yo (like my kayak riding short, choppywaves) so I have to up the air pressure again. Guess must be the springs as much as anything else. The new Rancho 9000s have 9 settings, so theoretically you get a wider range. However, the in-cab control gives you the ability to set any pressure range from zero to maximum, so I suspect the new 9 settings Ranchos just give you more options on the manual clicker.
BTW, I am running Ironman springs with 2 inch lift, plus greasable shackles that add another half inch. Glenn of RR tells me it isn't really necessary for me to put in longer shocks, but to spend the money on a dropped pitman arm instead.
Incidentally, I had pretty bad steering wander with the stock Sami shackles - despite putting in a return-to-centre steering stabiliser - until I swapped to thicker and stronger shackles. Arrrr, but the freight from the US to Singapore for the JPEater kit is a killer - US$340 by US Postal air, and US$140 by surface mail!
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Best,
Slowyak