Your piping routing looks great. I am in the midst of trying to install my IC as well and had thought about routing the return pipe behind the air box to keep things clean.
Anyway what did you use for your intake hat/pressure chamber?
I have a 2" long piece of schedule 40 5" pipe from my employers pipe fab shop that I am going to use to adapt to the intake manifold, but that is about as far as I have gotten. The I.D. of the 5" pipe is really close to the diameter of the intake. Do you have any close up pictures of the intake hat/pressure chamber?
Did you find it difficult to re-clock the turbo?