Regarding cosmetics...

How hard would it be to utilize the ML320 engine cover? It's the one that everyone uses with the needswings single... It leaves the center part of the intake manifold exposed, but covers all the nasty wires on the perimeter.

Also, if you remember, the passenger side of the cover has a big gaping recess in it. It's where the OEM Mercedes intake tube resides, and it would be a PERFECT spot to nestle the intercooler you're running. Literally all you'd have to do is make one of the intake pipes marginally shorter on the side nearest the core support, and you'd be able to use the ML320 engine cover that requires NO modification. It would look more symmetrical than the OEM airbox, and it would class up the engine bay with the Mercedes star.... a win-win.

I'll see if I can draw up something for you to illustrate what I'm referencing.

Edit -- Here's what I'm talking about: