Going to check this today on my 06 PSD with 198K on the clock. Started making this exact sound and hoping it's this easy fix. Thanks for the detailed update! ScottUPDATE:
Installed the boots and cold side pipe this morning. The original boots were cracked and leaking oil, but didn't have any tears. The cold side plastic pipe was cracked at the intercooler side, between the ribs, on the underside.
Took the truck out for a spin ... HOLY SMOKE! I normally experience some turbo lag, which had been concerning me for some time, but now it is completely gone. My cold starts used to be sluggish for the first couple of miles, but not this morning. I am truly shocked at the improvement. I highly recommend those with later 6.0s get rid of that plastic cold side pipe. I've read about its failure, but this just confirms the claim for me ... plus the metal pipe looks so much nicer under the hood.
I hope this helps others in the same predicament. Now, onto the next project; oil bypass filter.