I'm also considering a switch out to warn manual hubs and I hear you've had some experience on the topic. Can you point me to a thread that would help out concerning the installation process?
There is a TSB on Zukiworld this month on just this topic. Near mandatory reading, expecially if you want to lose the shift-on-the-fly stuff at the same time.
But did you say 2004 GV. My brain is mushy, but the 2004 models years have changed. There's something funky with the front axle, but that might just be the XL7. I'd need to see a pic of the axle to tell you for sure. If so, that's totally uncharted territory. Could be cool, might not be cool. I dunno. Frankly, the new axle frightens me soley because I don't know how it works or what's inside exactly.
Now I sound ignorant, afraid of the unknown and all.
But, someone else posted somewhere that the rear carrier size changed too and the 12-bolt ARB did not fit the newer GV ring gear. I do not know if a Kick 12-bolt pig could fit the newer housing "banjo". If so, no biggie. If not, then you would need to swap in an entire axle from an earlier GV.
Errrr, could this mean is there may be a possibility of no gears fitting the t-case, nor lockers for the rear axle, nor who knows with the front axle.
Before you throw coin down on any mod, you might want to check into these things. T-case gears is a pricy, but totally worth it, off-road prep item. But if you can't lock the front and/or rear axles, they might just be the only option you have.
I do know this. Don't buy a 2004 XL7 manual with the intention of installing a off-road package into it.