I've seen a few cars with this, and am curious about the importance of it. My priorities are longs ala Engman kit, suspension ears, and tying the top of rear shock towers to frame rail. How bad does this area need it?

It probably will help if you're going to go 180 with a huge rear wing.

It adds weight, and I didn't think that particular area needs reinforcement. There are a few areas in a 914 that truly need it under certain conditions. But here?

I've seen it on several AX cars, so I'm curious what their thinking is. Is there some real engineering behind it, or has anyone ever seen any evidence of flexing or cracking in this area?

The factory type reenforcements as shown here are to strengthen the sides so that the cross member that the transmission mounts to will flex a little less resulting in less flex in the rear area of the engine/transmission mounting box. The factory wasn't allowed to use tubes to strenghten things back there like IMSA allowed later on so they had to make things look "normal".

I call BS. I'd never put them on my car.

You may not put them on your car, but John has posed one of the first explainations that I can buy...it may have a valid point.

They are not doing anything for the shock tower, that is for sure.

I also would not put them on my car..you loose a 1/4 inch of room for your tire..and I need all I can get without rubbing the inner fender.

Rich

Until you start cutting a car apart in that section. It's a double wall made of thin sheet metal.

Welding a plate on the outer side of the double wall does nothing to improve the rigidity for the transmission mount bar.

Andy