Go with the K&N.. You don't need a hepa filter on that thing, the particles that get by the K&N filter aren't big enough to hurt a thing.
When the K&N gets dirty, go buy yourself a "recharge" kit, clean it up, and you'll be good to go.
It's worth spending a few extra bucks in the beginning, knowing you're saving yourself more money in the long run (buying new filters, improved gas mileage and performance).