KnN filters are indeed cleanable, they generally give less restriction and more induction noise, but can end up reducing performance by sucking in hot air from around the engine
They also supply ones to replace the standard filters in many cars IIRC. TBH I certainly wouldnt put a cone right on top of the carb, you need to either tube it to the front, as close as possible to cold air, or shove it in an air scoop.
The K&N filter is an interesting addition even if you dont want to go for out and out performance. Most of them used to be washable and had a better performance dirty than a clean standard filter, this is probably still true.
more airflow doesnt always equal more performance.
True, only if the car is tuned corectly do you get any advantage, in some you need to rejet the carb too. What you would end up with by just fitting the filter is more air getting sucked into the engine resulting in a lean burn.
Dirty air is more harmful than good, if that wasnt the case people would remove air filters and go filterless as thats going to get the highest air flow surely. *Guessing*
Theoretically it should but it depends on the engine, some suffer badly if they dont have a filter on. You certainly dont want to go without a filter as dust entering the engine is going to cause more wear than any gain in airflow will produce.
It also depends on the car manufacturer, a few have got their filters pretty damn near perfect.
K&N filters actually have no loss of power over an open airflow system.
http://www.m8auto-tec.co.uk/catalog/product_info.php/products_id/103110Yeah I know - advertising blurb but it was reported about 20 years ago in a mag which actually tested the filters that a K&N one gave better throughput of air after the Baja rally than a new paper filter and the flow loss over open carb was well under 1%.