I have 919's & a 1" spacer, I don't think the 919's give much more lift, but they do carry a load better. (I have a LOT of weight in the back, enough tools & spares to get home in the event of 85-90% of what commonly goes wrong "out there".)
Yes the axle geometry changes somewhat, with the most noticable difference being that the rear tires are closer to the front of the fender well. I haven't noticed them being off center, but when I hit large bumps at highway speed, I notice a little sideways deflection as the suspension compresses. Fortunately I'm a good steerer.
www.independent4x.com offers adjustable HD lower links that could compensate a bit, but you also have driveshaft overlap to consider.
They also sell an adjustable upper center link for Troopers, but I don't know if it will fit the VX.
A call to Matt will answer all your Q's.
Most here have installed 912's & cranked the torsion bars & lived happily ever after.