I also ran the Finer filters and found they worked well. Bit messier than the K&N to clean I found. Performance wise hard to compare as greatly different engines and a long time ago. What I do recall is there being minimal to zero visible migration of dirt onto the inner foam element.I am sure there would be finer particles, but nothing to the naked eye. Over time I did find the foam started to breakdown/crumble a bit, but by then I had well gotten my use out of it.