After a bit of contemplation I've decided to go for it. I don't really need 4300lbs, but I'm tired of living on the edge at 3480 lbs without water. And wondering if my 1850lb/C rated tires will blow if I have to hit 75 to avoid being smushed between a pair of semis.
And so I'm scheduled to go to Jackson Center to get the axle/wheel/tire/disc brake upgrade on Feb 13th and 14th. I'll let you all know how it goes.
(ps pardon for the multiple postings...the 16' Bambi GVWR issue had a few threads)