Should I "over build" the rear trunk structure

I am thinking of making a subtle change to my build, going with a fiberglass rear bumper instead of the stock bumper. Since I need to replace the rear trunk support brace anyhow, I was wondering if I should replace it with the extra reinforcement pieces normally for the Convertible. The cost is negligible, only another $60ish worth of parts/brackets, and I will have a lot of work back there anyhow. I know the added structure means nothing for actually mounting the fiberglass bumper, but I was thinking in regards to extra structure in case of an accident or something. Any thoughts from you guys? Is this a good idea or pointless over building?

The only structural changes I think are required would be to stiffen the chassis to make it better suited to performance driving. Beefing up the rear for added collision "protection" seems a waste of time and money.

I'm with Terry on this one. I've seen pics of wrecked verts and they crumple up just like the coupe. If you are worried about safety, I'd get tank armor or a fuel cell. If you get rear-ended it will sustain damage no matter what. And if you were to somehow create an indestructible rear structure, the whiplash you get will be more of an issue. That's my .02 since you asked.