Wow, crazy amount of fab work here. Very cool build.
Good point on the cabin vents. I thought those GM door jamb vents were to release pressure when doors were closed (and windows shut) but it makes sense that it would work with outside air intake as well.
As for your worries with the fuel cells, have you considered a carbon fiber driveshaft?
And holy hell, those are the thickest brake pads I've ever seen