Air filter: keep K&N or replace with foam?

Just sold my heavily used TE510 and picked up a near-new TE450 with all the goodies.
Can't wait to go riding.

Not sure about one of the goodies though - the K&N air filter. And sadly, I didn't get the stock air filter cage (so will need to buy one if I go back to foam filters).

I always ran foam filters (mostly TwinAir) and red No Toil on the 510.

So - keep or ditch the K&N? ...and some sub-questions:

1. Does anybody run K&N in the dusty or sandy areas?
2. Is there a foam sock to put over the K&N?
3. Any consensus on the best foam filters?
4. How about the red vs. green No Toil?

BTW - I was on ThumperTalk in past, but not very active. Just joined here, first post...

I would ditch the k&n and use a twin air.

me 3 (twinair) go foam or go home!!!

I had a k&n on an old TTR250 which a friend now owns, it has over 10,000km on it now with the k&n on it for all of that time. It still runs perfectly on original piston/rings, valves never checked. I am convinced it filters well but it is harder to clean. I would recommend the foam on any dedicated dirt bike though.

Thanks guys. I use a K&N on my Moto Guzzi. But the consensus seems to be ditch it for the dirt bike. I also talked to Mik at Motospportz. He likes the Moose Racing filters with the neoprene gaskets. I like that those don't require rim grease. Two on the way, along with a filter frame and an axle nut. Decided to try Maxima's foam filter air too - have always been satisfied with their other products.

K & N seem to make filters with really free flowing air, but at the expense of fine filtration. TwinAir are specifically designed for dirt bikes to give the best protection in dirt, mud, dust water etc. If a TwinAir is blocked up, it may knock a few BHP off the engine power, but most dirt bikes are way over powered for 99% of riding situations. Leave the K & N to tarmac track racing or supermoto where every BHP counts.
I bet a K & N won't hold the water back during a deep river crossing just long enough to get through without drowning the bike!

That last part about water crossings is a good add. My stuff showed up yesterday. Now I can go get it dirty without worrying about sucking all kinds of abrasives into the engine.