that is a false statement. I ran no filter just an empty air box for one year on a 1397 tore it down and sold the cyl and pistons, when the buyer received them he said" I thought these were used? they look new" except for a little cabor on the piston crowns.Stock is best.
The problem with aftermarket air filters is they need to be dirty to work and when their dirty they don't flow as advertised.
When clean they let through too much stuff that can scuff your cylinder walls.
I'll stick with stock.