I had gotten an undercar chassis brace at the 'mall' some time ago. It bolts to the diagonal arm mounts, very simple. It's sort of a mustache bar, somewhat curvy. It's made by Volvo, and my friend says they come on the cars in Europe, but here there's more demand for soft ride. I had had the impression their effects were less noticeable than the braces that go across the engine bay, connecting to the tops of the strut towers, but I was misinformed.
I put it on the other day on my 93 turbo sedan.
Well. I now have a new car. What an amazing difference. Control, road feel, even front/rear coupling seemed greatly improved. I now have that hugging the road feel I had felt was missing in this car, even with the Bilsteins I swapped out from my 740.
I expected to notice something, but this was just... amazing. So, I highly recommend that if you see one of these, to grab it. They fit 7/9's so a wide variety of donors. And, I'm now looking for another for my wagon.