I still think that a very nice street Contour would have big bars front and rear. The reason for our low-speed plow is not too much roll stiffness, it's chassis stiffness and more importantly, front camber. I'd bet that increasing front roll stiffness would have a greater improvement on corner speeds than the rear, since the front tire has such poor camber in roll.
In any case, suspension tuning is not a black art, but it is also not as simple as some people make it. The whole package: roll bars, springs, bushings, static and dynamic camber and toe, chassis stiffness, tire pressures and sizes, strut valving, etc.; all work together. A car with a particular set of springs and struts will react very differently to a different bar than a car with another set.
Also, a car that feels like it handles well on the street may require a very different setup than a car that really has higher limits, which is probably different than what would actually get around a road course faster. Transients, steady-state cornering, braking, ride comfort, and more are all comprimised or aided by different modifications. Balancing them requires quite a bit of thought.
