I want to say the intercooler was a powder coat of some kind, as was the upper intake.
I've used alumablast myself on different things (brackets, etc), and it turned out well. Eastwood offers a 2k version of alumablast now in a rattle can, much tougher and fuel resistant.- Suit up/respirator/paint outside if you use that stuff though, isocyanates aren't anything to mess around with.
I had really good luck with plastic media blast and Diamond clear this last time around. The attached pic is bare blasted aluminum and clear.
I'm more than a little curious about vapor blasting... would love to see what a vapor blasted upper/lower looks like.