Keep in mind, that when these cars were designed, the total suspension design revolved around "X" inches of sidewall, with spring rate/shock (engine size/weight) etc.
Reason I bring it up, was that I was looking at 63-65 Lincoln convertibles about 10 years ago. I visited a shop that did nothing but Lincolns and spoke with them. The tendency for the younger collector (we'll call them), was to put 20" plus rims or "doinking" the car.
He had lots come to him asking why they were getting steering wheel wooble, bumpy rides. Basically the rims were getting bent from lousy roads (here in New England). The cars weren't designed to NOT have sidewall as the initial absorber of any bump.
Keep in mind, that these were supple riding cars (in the day). You add a "sport" (stiffer) suspension and the problem could only be more pronounced.
It will definitely handle better with less sidewall "roll", but there is a downside....just sayin'
Just my .02
