No one on here has a dog in this fight. It's your car and your money, do as you wish. But as is the nature of what an online forum is, be prepared to support or defend your decision with facts or experience, or at the very least try to be open minded to the facts or experiences shared by others.
You are happy with your K&N air filters and seem to like them not for their perceived performance gains but for long term cost savings and maintaining them yourself?
If you stick to the Infiniti maintenance schedule of replacing the air filter every 45,000 miles, considering a K&N filter costs ~$50 and an oem filter costs ~$25, you will start to realize cost savings after 135,000 miles...! None of my cars have even half of those miles, even my 20 year old car, so I can't even begin to rationalize this.
As far as you liking to maintain them yourself... why? Every year, for my 25 hp carbureted lawn tractor, I install a new air filter and have to oil the foam pre-filter. Coincidentally, I use the red K&N filter oil so I can verify proper coverage. It's not a big mess, more of a nuisance, but it is recommended/required for my lawn tractor so I just deal with it, but still, yuck...
Now the main concern with K&N air filters that p07r0457, Timothy Sigue and I are trying to express to you is the subpar quality of the filtration of air provided by K&N air filters.
Have you ever rebuilt or even bore scoped your engines? You may be surprised what you find... I've rebuilt several motors and also have an endoscope. I have personally seen the before and after effects of running a K&N air filter. On my buddies car, you could initially start to visually see the scoring on the cylinder walls but couldn't really feel them by touch. Much to my chagrin, he continued running the K&N filter and then they became much more pronounced and that's when he decided to swap back to an oem air filter. Guess what we found after running on the oem filter... no further scoring had occurred! Somehow his compression test results were still good but the damage was done so we ended up sending the head out to be bored and honed and we built the block to support gobs of power. After the money he put into that block, expensive lesson learned but he definitely won't touch a K&N filter ever again.
Originally Posted by __XIS__
regardless of some opinions, I have been using K&N filters on multiple cars for over 35 yrs without one single solitary issue. A couple of the cars I have driven over 10 yrs and my EX35 has had one for 8 yrs, the same one. I will continue. It is usually one of the first things I do when it is time to replace a filter. I also like their oil filters, but I don't use them exclusively like the air filters.
I have not mentioned 'power' or any other benefits other than I like them, I like to maintain them myself and I don't like to buy more than one for the life of the car. Batting 1000.0 with them.