Here is a patented "Eddie Theory" (TM), which I'd like to hear more experienced chassis builders/modders and racers' opinions and experiences on:
Wide, extra-low profile tires will make a swing axle car handle worse.
When (not if, when) a swing car's rear axle "jacks" during S-turn maneuvers at medium or high speed, a very good, wide, low profile modern radial tire will ride on its sharp outer edge, providing a relatively smaller contact patch than a more pedestrian, narrower tire with a taller sidewall.
This is because sidewall stiffness—so important to making a good tire handle predictably when G-loaded under a modern suspension that keeps the tread face oriented consistently toward the road surface—will tend to keep that wheel "tucked under" longer when the weight returns to it. This should make the car more prone to snap oversteer than it would be with a softer-sidewalled tire that "gives" under that condition.
If you can picture it: the standard 165/80-15 all-season type tire, having a somewhat rounded shoulder, "rolls over" a bit on its sidewall and then kind of skids out from its jacked orientation. Ugly, but relatively controllable if you're the kind of driver who experiences this kind of thing once in a while.
The baddass 235/35-17 summer/track tire, by contrast, being aggressively squared-off along its shoulder and rock hard along its 2-inch sidewall section, tips up on that pointy edge, where the soft tread compound tries to hold grip before very suddenly letting go.
Makes sense?
Again, I've not yet tried to prove this out on a track, but I wonder if any of you have relevant experience.
Vred sprints, 165/80: 
Bridge potenza, 235/45-17: