Thanks for the comments everyone; appreciate your input.
Frank, lol. Honestly in my short test drive the car felt more planted. But we'll see.
Neil, good call. This is a situation I am aware of and concerned about. My pan is really anchored and stretched about as taught as I could get it. So I don't expect it to deform or parachute at speed. That's the main reason I went on my test drive though, to listen for it flopping around. Hopefully I would hear it over road noise. If I had a camera I absolutely didn't care about I might think about strapping it under there... But even in its static shape it could catch some air pressure, so I might look into making some small side panels to somewhat seal it off.
bgd, I don't really follow. I don't think any of the parts hanging out under the car rely on air flowing over them for structural integrity.... static dissipation was not something I considered though, by any means. Your sube got struck by lightning multiple times?!? Please elaborate on what you did so the rest of us could avoid such a ridiculous situation!
Really don't expect the rear struts to warm up appreciably from this mod though. The panel is only 30" wide, a good foot away from each strut. The exhaust runs pretty cool under cruising conditions, after the manifold, turbo and catalytic converter suck most of it up. Being a diesel, and with my aero mods, I'm not requesting a whole lot of power most of the time anyway.
I think this will be the last major mod for the underside. Its pretty smooth now in general. The only other thing I am thinking about is adding a little lip spoiler up front to let less air get under. The curved noise of my car kind of shoves a little more under there than is needed, I think. Maybe this thing:
