I am going to be pulling the flies on my 2007 ZX14 with a slip on exhaust and was thinking of going with a aftermarket air filter. What brand would you recommend out of a K&N, BMC, or just keep the stock one? Also wondering if I should put a Power Commander on the bike with the flies out, slip on, and air filter. Thanks.

Unless you road- or drag-race, keep using the stock OEM Kawasaki air filter because it works great.

According to Brocks and others who race, putting an aftermarket air filter in a ZX14 is a waste of money.

The PowerCommander won't know what air filter you have in, either. Not enough difference.

keep using the stock OEM Kawasaki air filter because it works great. 1+

Cut the screen off the back of the OEM air filter. Someone figured out this trick smooths out the pulse. You can feel that slight difference. If you run race filters, you are tearing down engines and monitoring compression. These let in grit along with de-restricting the air like the OEM and that screen slowing the air does now.

The cuts in the cylinder walls using a more breathable filter, or a poor fitting air cleaner cannot hold back the larger microns or huge things you can see with the naked eye, like grit sucking around through the leak? Say you run without a filter or a leaky filter in place, where the stone drags itself over a chalkboard but leave no chalk, rather removes the chalkboard material instead.

Down the road, you will have more compression than the more hard core race filter kind of street rider. As a used bike buyer, which bike would you rather invest in, knowing the difference if you asked what is the history of changing that filter element?