Those filters are just pre-filters for the intake ducting - they do not need to be 'better?'
Just get a block of open cell foam (sold in varying degrees of coarseness), use an electric carving knife to cut the foam to the desired size and install them in place of the OEM filter, but keep in mind that if the foam is too fine, it may cause the engine to run rich and too too coarse it may let in too much dirt for the actual filter to handle. It will simply shorten the life of the actual air filter.
I know some performance freaks that remove the filters for maximum air flow - they say they will just replace the filter more frequently - in actuality they install a K&N filter and say they paid $75 for a filter that will last forever, but they fail to buy the air filter service kit - they end up never servicing the filter and then can't figure out what caused the engine to fail in a single summer of riding.
Shop Owner and Mechanic with over 50 years experience