A few comments:
1) The oil in the intake tract is not really desireable, but it is pretty normal. Most of the 603's that I've opened up are oily in the intake tract. It's probably from the PCV system more than the turbo seals. I actually found a document in the WIS that says no warranty work is to be done to correct this, because it's normal... but I was never able to find the document again so I could make a PDF of it! (Some day I'll figure out where they're hiding it, lol.)
2) I used less than one quart of Mobil-1 in 10,000 miles on my most recent oil change, with 270kmi on the clock. A quart in less than 700 miles is definitely excessive.
3) A cold compression test may show if one or two cylinders are far off the others, but a warm/hot test is much preferred. The absolute numbers will be useless though, if done cold.
4) With that oil consumption, and a 3.5L engine, I'd be pretty surprised if you *don't* have a bent rod or two.
Only way to know for sure is to yank the head and measure piston protrusion.
5) For the delivery valve seals, don't forget the torque sequence... 30Nm, release, 30Nm again, release, final torque 35Nm. (The procedure is in the TDM, not the FSM, for reasons that still escape me.)
