Massive Black smoke, towed to dealership, what the problem?

[lurky]

Hi
I was driving my 2007 Boxster home last night, heard strange whistling noise from engine whenever my foot was not on gas. Engine light goes on and off, then I realize massive amounts of smoke were coming out of back-end. Engine making more weird noises, I pull off highway and have it towed to Porsche dealership.
I see black oil leaked out from under back end of car onto the flatbed.

Now Porsche dealership is doing diagnostic, still trying to figure it out, they say oil is everywhere, in air filter, coming out of tailpipe, everywhere. Not sure where the leak is yet.

Any ideas?
Thanks