Well, I didn't know about the ackermann theory . . . heard the term though. I do know that when the steering rack is in front of the front axis, when you turn, the wheels will toe in. Vice-a-versa when the rack is behind the front axis. As far as scrub radius effect on handling; our formula cars have extreme amount of negative scrub radius. The pivoting point is almost at the inner side wall. For a street car (with all the weight) this will cause the steering to be extremely heavy. Also, if your running alot of negative caster your tires will stand up on their side walls.

I've always been fascinated with all the different variables and how they interact with each other to change handling performance.