K&N 204 is what I use. A lot of people use other brand filters and they seem satisfied. I've done more than a dozen oil changes and I haven't replaced the washer.
In a side note, if you're going to do your own oil changes and other maintenance, you will want to make good records to keep your warranty in tact. There are apps for your smartphone that are good. Hand written notation is fine too. A lot of people already know this, but I thought I'd mention it just in case.
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Male, 44yrs, 180lbs, 5'9", '14 (RWB), 22k miles, Bridgestone BT023, Vortex V3 kit, Rotella T6, KN-204 filter, 87 Octane, Maxima Chain Wax, Puig 6479W windscreen, clear signal lenses, Fork Preload caps, T-Rex spools, Radiator guard, Shorty adjustable levers, Fork stem RAM mount/USB port, red/black alum grips, 300R Rear tire hugger, Rear seat cowl, LED engine/undertail lights w/RF remote, LED position light, Sea level, city commuter, spirited rider, turn my own wrenches.