Newgroups are a great source of misinformation, so here is something to
consider

The k&n filter is wire mesh with cotton element embedded across it. It is an
oil trap type filter so the actual pore size of the cotton is fairly large
but by giving it an oily coat the fine particulates will stick to the cotton
and create a filter bed as it collects more dirt. So the filter becomes more
effective as dirt builds up on the surface. Of course at some point it
becomes clogged and restricts air flow. The whole purpose of this filter is
to give you more air than the stock filter which will in turn give you more
power (doubtful). This is a trade off for allowing dirt in the engine for a
tiny increase in power or a cleaner engine and greater longitivity.

The standard air filter is a woven media that is pleated to increase
substantially the surface area of the filter. This allows for designing in
an absolute pore size in the material that is very small and still allowing
adequate air supply assisted by the pleating.

Abrasive material (also known as "dirt", "crud") that is sucked into the
engine will wear out the engine, both in the upper and lower end. Effective
air filtration and oil filtration determine the life of the car. My opinion
is that the goals of increased air flow for additional engine performance
and extending the life and reliability of the engine are somewhat
incompatible in this case.....the way the engine gets more air in this case
is by reducing the filtration capacity of the intake air filter. That lets
in more dirt....the mfgr. uses pleated filters to give large filtration area
and lots of protection and still allows for relatively hi rate of flow. The
pleated filter will not plug readily and pressure differential from indeed
to outfeed will remain constant for a long long time. A filter bed type
filter (like K & N) will tend to increase in pressure differential until it
becomes completely plugged (you would notice this as a loss in power, poor
mileage, poor idle and driveability). So it's "good" operating range is
narrow....new it lets in dirt, old it plugs up.

I took the K&N out of my Legend with no decrease in performance or gas
mileage. I have noticed when I change my oil, its cleaner with the OEM
filter that the K&N .... that's something to consider !

The oil you use on a K & N can ruin MAF sensors, but I think the Legend uses
MAP instead so may be less of a problem with oil contaminating sensors that
determine fuel/air ratios.

If you think a K&N filter is better, buy one, use it and enjoy it.  Or why
not disconnect the complete Legend intake (very restrictive) and add a short
ram or cold air intake and even more air (and dirt ) into your motor ....