K& N filters are better because they flow more air when they get dirty-proven scientifically by an engineer & famous engine builder named David Vizard. If you drive in the clean air of the North (Nebraska, Montana, lots of Canada) in a low compression V8 or slant 6, it probably is over kill vice changing your filter often. Spectre and others might be another viable alternative.
Fuel cleaners & oil cleaners are not usually/or-as necessary anymore due to detergents in oil. A 1/4-1/3 a can of Seafoam in every other gas tank should be sufficient. I personally do not run 87 octane where I live because it is not as filtered anymore (pump some into a gas can and look at the flecks of tar floating around {in bright sunlight}as your test where you live) and leaves people stranded with clogged fuel filters and pumps) I am referring to the 87 octane 10% ethanol that I have available.
Either Seafoam (as a detergent), Stabil (as a fuel stabilizer for long term lack-of-usage), or a water remover is about all you need as an additive for fuel. As mentioned above, something that combats the water combining with the ethanol is also beneficial.
Let someone like Ramenth give you hard data about oil additives.