Gerard, as I understand it all six wheels on the Xplorer are the same, 16" 8-lug 'SRW' type. So there's no difference between front & rear. The GVW would not increase. You might be old enough to recall seeing similar adapters in the JC Whitney catalog.
The Dodge 3500 van used a large semi-floating rear axle rather that the full-floater you might expect (at least my '99/'00 Dodge Roadtrek did), and the track was narrower at the back than the front. In my case, wheel spacers did _not_ improve handling. Speculation on this forum back in the day was that Mopar had avoided the tooling costs & extra parts stock of a van-specific rear axle by using the axle from their 1-ton pick-up.
The one new Xplorer 230 that I saw on a sales lot in '02 or '03 seemed to sit pretty high in the rear. Dunno if they'd added extra springs or what. Yes, most B's sit kind of low with all the hardware that's hung underneath, the early this-century Roadtrek Chevy's being prime offenders. But I took my '01/'02 RT C190P up several dirt roads that were pretty challenging with no ill effects.
IMO, except for serious handling issues, my Dodge RT was a _fine_ class B. It wasn't as winter-capable as the later Chevy's, since the water tank was external. But the fit & finish were superb.
Jim, "Protect your bagels. Put lox on them."
