I have the front and rear strut braces made from ultraracing and also the side under fender braces too.
I haven't installed them though.
The front strut brace didn't look that good due to the colour on my vr4, hence I stuck with the whiteline stuff. As for rear, same thing.
They are stiff and the fender brace things I thought I'd try, but they are designed to be held with nuts and bolts which I don't think will assist that much. Plus the added weight put me off a bit, also the fact that a cage would do a better job at stiffening the chassis.
Anyway, they are good quality bits.