Body Braces
In short, Yes. The extra braces do help. They transfer the flex that the body and frame may experience back to the suspension, where it belongs. They are not perfect in this, but they do make a noticable difference. I believe there was another thread on this subject that explained it better.
Just as an example, our 87GN got the braces under the front end and behind the seat at the same time we rebuilt the suspension...all together it made a world of difference to handling. I still have the body bushings to replace, but the dashboard and the steering wheel stopped shaking over bumps, the T-tops are hardly ever heard any more, and the car can now take a corner without making you $h!t your pants. I don't think I would race a slolam course, but the improvement was grand. :biggrin:
As a single add-on, I would think they would be worth the money. Most would agree.
Don't know about the radiator brace, ours has always had it.