Here is a link to Alcino's car in action. He built his car for autocross (if memory serves) and runs great! His car has been featured in Popular Hot Rodding because of how well it handles. You can do a search for Alcino on this site and find a general idea of what he has done to the car - I don't remember what the PHR article has to say.....
http://www.stangnet.com/mustang-forums/threads/track-day-video.740128/#post-7383669
There is also a link on the .net site concerning front springs. The short story is if you want to handle, the front springs need to be a little beefier. The original units are pretty soft to give it a "luxurious" feel which is what they were going for back in the day.
http://mustangii.net/stifferfrontsprings_faq.asp
As far as the physics of the 2 different
suspension set-ups, I'm not sure I can verbalize it. I think I am going to relate it to how the driveshaft engages the diff. In the control arm set up when the axle travels up and down, like when you hit a bump, the axle *should* remain horizontal to the ground throughout it's travel. The leaf spring setup can basically travel in an arc. Also, the
control arms, if done correctly, can help keep the axle located longitudely(sp?). The leaf spring set up, it can move unless you were to install a
panhard bar. This is what Ford did with the 05 and up Mustang's to prolong the life of the solid axle before finally moving on to the IRS, although it was using a control arm set up. Regardless, you will want to keep your axle planted firmly under the car for handling purposes and
panhard bars help do that.
Handling characteristics depend on a lot of different factors: center of gravity, spring rates, tire sizes and compounds, vehicle weight, weight distribution, etc etc etc. Look to balance the weight front to back the best you can, i.e. relocate the battery to the trunk. Remove weight from the front by installing aluminum heads and intake. Lower your car - there's a reason race cars sit so low. Widen the tires on all four corners to increase the contact patch. Raise your spring rates so the car doesn't produce as much body roll. Locate the axle, again to control the body. There is so much you can do without having to try and engineer a rear
suspension in your car. Alcino's car is a great example!! If you haven't gone through his PHR article, you should!