[Perfectlap]

^ and cut open the filter so that you can unroll it. The recent Excellence magazine article on the LN upgrade said that fragments the size of cracked pepper bits are cause for concern. They give the exact measurement of the bits.
Some people wait to change the IMS so that they can do the clutch at the same time. I personally don't think you should wait. Do it now. You may be prematurely changing your clutch but that is only a loss of less than $600 vs. the possible loss of a $10,000 for a new engine.