Drop in filters are great for ease of install and retention of water rejection but will not flow as much as a large cone filter. Green makes a panel filter that drops into the stock box that outflows the K&N and of course the stock filter for $65 delivered to you.

Green also offers a cold air Twister filter (see post elsewhere) that takes a large cone filter and puts it inside a cannister that pulls from the fender where the stock air intake is - the Calmini is just a cone filter with a bracket and it will suck horespower robbing heated air into the engine. Nice kit but questionable performance increase due to the hot air it injests.

More clean air is always better - Green filters down to 5 microns - others do not...