Roy. I did the autoX and my car is a pan with no reinforcements. I think I even beat somebody.
So what if the pan flexes in the auto cross? So what if you loop it? There’s plenty of run-off room and you’re not likely to turn it over. (And if you break anything, we’ll help you fix it).
It’ll handle as well as it handles and you’ll get an idea about its limits. That will make you better able to deal with it on a twisty road, when the time comes. Since you had seat time in the originals, you already know what driving a primitive suspension means.
I’ve taken Bridget along some wooded stream roads and even reeled in a couple Brit sports cars in my day. As you know, you don’t have to be going dangerously fast to have a good time.