They're very light (probably less than 5lb, as a full set of door and quarter panels only weighs 7lb), because they're aluminum. Here's one I did a while back.
I think the Super engine compartment is same as a Std.
For the firewall, you'd probably want to paint it, clear it, or powder coat it. I say that just because of the heat inside the engine compartment. Aluminum will oxidize over time if not coated. For the race car interiors, we just keep spray wax on them (like Pledge), but I don't think Pledge would stay on very long in the engine heat. The heat won't hurt the firewall, but it wouldn't stay looking good without some coating or some routine cleaning.
