Couple things in that last pic, the cap on top of the cowl is where you add coolant to the intercooler system. The other is the hoses you see are just mock up to get the lengths needed.
This cap is connected to a tube that is at the highest point of the intercooler (and the entire intercooler system). It is a fill and bleed point. I have a bleed on the intercooler radiator as well.
And this is the back side of the firewall where the intercooler mounts that shows where the discharge pipes go. The entire intercooler assembly doesn't take up much more room than the stock cowl tub did:
I took some pics of the left side wiper build and this shows building a box bigger than its opening. I couldn't just bend up a box, I had to build it in pieces and assemble inside the hole:
After assembled inside, I could then weld it:
I need a flange inside the box that the lid can bolt to and help keep water out:
Didn't take any finished pics of this one, but its the same as the other side.