Originally Posted by DarkJak

I've noticed that too. It's such a huge gap, and the back is mostly solid. There are several aftermarket exhausts that still use a setup similar to OEM though, like Invidia, Akrapovic, Ark DTS Type 1 (did that ever go into production?), and probably a couple more I can't recall.

One could probably just put a flat piece over the entire area to cover it up if the drag really is significant.