I really like my vacuum setup, it is also backup for my brake booster if the engine dies.
I'm still looking at park brake options, I will probably go with a hydraulic lock on the rear brakes.
I'm not sure on the ABS, I disabled it on my Chevy 3500 by removing the fuse.
With the Volvo portals giving you 5" of lift, you should re-think the 6" lift. I have the 2" OME springs which gives me 7" of lift and with 38.5" tires that makes it pretty tall (45" to the center of the front wheel well). I think anything over the 38s would hurt the off-road performance and increase the chance of breakage.
With the stock Volvo wheels 11" wide tires are about as big as you can go without rubbing on the rear frame rails, so custom wheels with less backspacing would be needed for anything larger.
I think your driveshafts should work.
Can't wait to watch this build, I see this being a trend
