I did buy the oil from TWIN AIR, but didn't see the need to buy their cleaner, their cleaning container, nor the oil application container from them. (I found that any good butly based (water soluble) degreaser/cleaner (Such as "SIMPLE GREEN") works great and doesn't degrade the foam in any way. An empty 2 lb. Folgiers Coffee can works great for a "cleaning bin" and another is perfect for an "oil application bin". (I have a couple of extra ones if anyone would like to buy them.....I will make you a helluva deal: Only $19.99 each, cheaper than what TWIN-AIR wants for what I imagine is very similiar.)

Seriously folks, the TWIN AIR filter, coupled with that tackyass nasty blue oil that they sell with it is the "poop". Quick and easy to clean, easy to re-coat, and not real expensive, and GREAT protection for the engine with fantastic flow.

BTW, "alaska", the difference between the '02 and '03 air box is night and day: The '02 is a horizontal filter, with lies flat across the top of the intake (as you know) and thus, requires a lot of jogs and turns before the filtered air enters the carbs; the '03 on the other hand is verticle (it is somewhat circular and surrounds the carb intakes, and is probably 30-40% greater filter area by comparison.) And yeah, your right about "nasty"...I just finished re-oiling, and it will probably be next Wednesday before my fingernail cuticles change from blue back to pink.

 

I had a '02 650 & I for one was not happy with that filter design. Recently I sold the '02 650 for a Camo '03 650 & the stock New air filter design is by far - a 100% improvement. I have noticed better throttle response thru-out the powerband.
I have been using PJ1 foam oil on all of my Twin-Filters, with excellent results. I do not know why but I am also getting improved gas mileage with the '03 650 vs my '02 650, I think it has to do with the better air-flow with the upgrade air-filter design.
Both www.denniskirk.com & www.rockymountainatv.com are now carrying the Twin-air filter for both model years.

 

I put my twin air in a couple of days ago. I honestly can't tell any improvement, it may run a little faster with the stock filter. The blue oil is messy, but it may be a better filter than stock.

 

I didn't realize there was a design change in the '03 airbox...interesting. For the '02, I do like the TwinAir. It's a good product at a good price. K&N's are overpriced.