I'm running on B5 for the first time. There is a difference, smoother running, but haven't had to change filters yet. Does run better, but only slightly. Not the placebo effect. I'd say it runs like a tank full of diesel and a generous shot of Power Service.
And it was cheaper than the petro diesel across the street.

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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)