I have the exact same problem on my 2.5L. Looked at the pan - there is oil definitely coming from the plug and maybe the pan gasket. The pan gasket appears to be silicone (red). The front seal is dry.
Apparently oil is getting on the exhaust pipe and burning.
The problem just occured the last oil change (@ 80K) when I switched brands of oil - Havoline synthetic (used since new) to Mobil 1.
I wonder if this could be the problem; different seal swell rates between the two.
