After reading a bunch of threads about aftermarket air filters I purchased a enginaire filter for my scag w/b with 12. 5 kohler. I changed over last weekend and ran all this last week with the new setup. Old filter setup had to be cleaned everyday. The new filter setup after one week(20 res. yards, dusty and DRY) the pre-filter has a little dirt but is still looks like it came out of the bag, paper filter is still clean as can be. Engine seems to run better and have more power. The folks at enginaire were also prompt to answer questions or return phone calls Overall I think I made a wise investment.