$7000 for the RT several years ago.
The PureONE cost me $12 last time I found it.
The BMW shop wants $18 for the correct one. Not a huge savings there.
Then I spend about $8 per quart for Mobil1 15w50.
AND THEN I change all of it at anywhere from 3000 to 5000 miles.
I think the truth is, the Mobil1 will not break down in the R1100 motor.
And, I think, it can look incredibly dirty and still do its job.
When it "looks dirty" to human eyes it has particles in it that are sailing through the filter.
This means they are too small to do any harm to the motor. Even with the stock filter.