Ahsai

Just to give you a visual. This is from an '02 996 C2 but it should be similar for your car. As you can see, the inverse "u" channel on the AOS is partially blocking access to that manifold bolt with a socket. On top of that, there's a very fat harness right on top of that bolt also, depending on how that harness was tied down. That's why step #2 is important in this situation.

Another way is try to use a 10mm stubby wrench to get on that bolt. It won't be possible in this photo as that fat harness is in the way but it may not be in your engine.