I've been using Rotella synthetic too, from using Mobil Delvac 1, and I notice less leakage. My car uses oil while it's parked, and I haven't added any since the change around 2 months ago. I think it's good oil, and will go back to Mobil 1 for the extended oil drain interval, but Rotella is a good 2nd choice and works beautifully in a pinch.

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'02 BMW 325i
'85 300D 450k
'93 190E 2.6 170k(killed by tree)
'08 Ducati Hypermotard 1100S 6k
'06 Ducati S2R800 14k(sold)