...just to throw a little more fuel on the fire, how about this: spherical bushings simply transmit everthing through them, past the boxes that are solid, and into the frame somewhere. Rubber bushings that allow the
control arms to move around in the torque boxes hit the boxes harder, since they are the first solid thing after the rubber bushings and they are actually getting hit now by any movement.
I can see this one going either way as well...
I don't have any real answers -- only what's been relayed to me and my thoughts on things. There are plenty of peopel who make these things work no matter which way they go. I think the only right thing to do is do your own research, talk to people, and decie how much (if any) you are willing to risk by going to a more race-oriented setup.