I don't have any solid driving impressions of this change yet, which I posted about over here:
http://986forum.com/forums/performance-technical-chat/12915-diy-rear-suspension-brace.html#post114410
At least there are no creaking or noise issues and the car feels solid and performs fine. I had it up to 112 mph this morning, no problems.
Franco, you're right that just a thicker plate would probably accomplish the same purpose, if not even better. You could also use solid flat bars instead of round to do the same thing and with less fabrication work. I'll have to take another look at the plate to see how much work would be involved with making a new one, but I imagine it's going to be a lot tougher than these lower stress bars. I know there are a couple air scoops that re-direct air up to the transmission for cooling that are attached to this plate, so that would have to be part of the design too.
As for the eye bolts... well they use the same kind of design on most upper strut bars, so I imagine it's stiff, but there is no question that making the Ernie Bar with one solid piece of aluminum is stiffer yet. I used the eye bolts on the smaller stress bars just because that was necessary to fit them into the slot where they mount and they made installation MUCH easier.
By request, here's another picture of my assistant showing off the hardware while wearing something a little more silky...
Kirk