I have a KWT X2 pre-production 3D printed pre-filter I have been testing. This is 682 miles on a new filter. Pretty impressed. My next report will be at 1000 miles at which point I hope to switch to a production model. Check it out:
Particle Separator - KWT Filters
KWT Filters particle separator revolutionary cyclonic technology separates particles and dust before the airflow reaches your stock filter. The KWT separator requires no fan or other moving parts. Installation is quick and easily done with basic tools.
www.kwtfilters.com