I have looked at the Pedders T5 rear lift kit, possibly from a previous post from you symcro. By all accounts it improves as you say 'stance and towing ability'. And general handling from some other reviews. What we're unsure about is how much the rear will be 'in the air' when it's time for bed. (2 adults + 2 young kids). You don't mention this. We generally sleep heads to front. Don't really want heads down hill,or to have to use leveling blocks on a flat site to compensate. Although not the end of the world if we have to, and we rarely camp in perfectly flat sites any way.
Our 2007/8 Cali 4motion does have the saggy rear that seems common and since we also have a NZ spec 50mm square removable tow bar which sometimes holds a steel swing out bicycle rack,and a few bikes,it only seems lower. Even at walking pace we can hit car park speed bumps with the tow bar and at gentle twisty gravel road speeds we can bottom out the rear. I'm guessing it's hitting rubber bumpers,but don't actually know. BTW, I've added up approx weights and we will be under GVM 3000kg.
Another poster mentioned they had fitted the Pedders rear T5 kit and were now hunting for a 20mm front lift to level it out. What's odd is that even with the rear end seemingly quite low,the inside sits resonably level. (Yes,I even checked with a level.)
So, first option is do nothing,and live with it, or upgrade; save a bunch of cash and fit the Pedders rear for that better rear ground clearance/wedge look and better driving feel? or go crazy and give Seikel and TNT (shipping to NZ and local taxes, fitting and balancing) a whole bunch of dosh and go up a "theoretical" 30mm all 4 corners?
http://www.seikel.de/shop/lift-figures-t5t6/?lang=eh
As we do drive a lot of gravel roads this is not a luxury or image decision, more a necessity. We don't do real 4x4 stuff.
Quietly wishing the Cali had come originally with the NZD$500 option 1BJ, Heavy duty suspension for rough roads with 20mm lift. But it didn't.