Well going back to the original post and to provide some balance; my ES TD5 has had both the air bags and ACE removed and replaced with Terrafirma springs and shocks and some very serious anti-roll bars. I'm very happy with the handling (and yes I have driven D2s as nature intended), and I like the fact that I have two less bits of complex and aging hydraulic and pneumatic gadgetry to worry will fail in some inconvenient spot.
I'm running standard height and weight springs on 255/55/18 KO2s, but am considering upgrading to Old Man Emu shocks and getting some 235/75/16s on steel wheels for dedicated overland travel. Not sure what advantage you would get from going much wider.