With the K&N filter you get a nice sticker that warns subsequent owners and the lube monkeys at your service place not to throw it away.
If you do the figures for K&N plus the cleaning kit v. the standard replacement intervals you'll find they come out pretty close to even, and the cleaning routine is not a real pleasurable experience.
Pays you money, makes you choice.
ADDED: 2014 GT 5.0A conv. black: electronics, comfort, security, CA plate (FLICK U); assembled 06-13-2014, delivered 09-25-2014; odometer today (03-21-2016) 4,321.5(--> DELETED --> 2013 5.06M coupe, black:: Odo LAST day (09-25-2014) 7,975) (--> DELETED --> 2008 GT/CS: Odo LAST day (10-22-2012): 9,719.3; #2075 of 2509 convertibles, #560 of 718 in Ebony. 2009 GT/CS: Odo last day (09-08-2012): 12,000.1; #34 of 1705 coupes, #3 of 377 in Performance White. <-- DELETED <--)