I own 3 intercooled turbo diesels. My 99.5 Jetta has a small, side mount intercooler and will run intake air temps about 20*F above ambient. The F350 has a front mount... not sure what that runs offhand.
The 2012 Passat has an air-water intercooler... and I haven't found where it reports intake air temps in the computer. It has an extra electric water pump (a tad larger than the one MB uses on our cars for the HVAC - VW uses this same pump on some of their cars for cool down after engine shutoff).
I'd love to do an intercooler on my SDL, and was looking at things that could go where the factory crossover pipe are. The issue I see is clearance with the hood... I don't think there's much space there
-J