Why is the Forerunners coil spring set up better than leaf?
I prefer coil to leaf because it's ease to lift but alot of people debate the bennefits of the two.

We want to disconnect our swaybars for more articulation, but don't like IFS? Do solid axles "articulate" better?
Yes and Yes. IFS doesn't articulate as well as solid, one wheel moves up the other does nothing. Solid you push up one the other moves down (a little), plus soild has more travel.

Why do we like to mount spare tires to the roof?It would seem that the weight and it's effects on center of gravity would be bad.
I don't, keep all weight as low as possible.

Besides, with the hitch, my spare isn't really the limiting factor for my departure angle. Any info would be appreciated.

Even without the hitch the spare isn't much of a problem, the rubber is the only part that touches anything. I've only seen the spare ripped off once and it was Ivan that did it which explains it. :p