Every K&N automotive filter I've seen cut open never impressed me, makes me wonder if their motorcycle filters are any better quality or not. I think Champion still makes them for K&N to private label. At least while factory warranty is in force, its not a bad idea to just use the Ducati oil filter. Strap type oil filter wrench has always worked well for me for removing filters.
On the Testastretta 11* the bypass valve is on the engine and so the oil filter may not contain one.
On the Testastretta 11* the bypass valve is on the engine and so the oil filter may not contain one.