I couldn't justify the $70 for the K&N for the bike, especially with all the discussion about them. I flip the extra $$ and use K&N oil filters on all my other vehicles where they make one, and have used the K&N separates in the past.
I use a UNI filter and have no issues or problems with it, for the past two years. I think they are around $25, and are resuable. The BMCs will run you in the $50 or so, and I might have considered those had I known about them at the time. Most probably suggest the BMC over the K&N because of the price, but from what I understand they are a good choice as well.
As far as the jets, re-read Ken's article again. He explains that Kawi, because of the valve controlling the flow of air into the float bowls, installed huge main jets in order get the gas flow needed through the bowls. The airflow into the airbox is not equal to the airflow into the float bowls. Kawi compensated that by using bigger mains.
Bigger mains does not mean bigger, better, or more power. Your main jets want to be a size that the motor continues to build power as complete as possibly through the entire RPM range (5-6k or so plus). Too big of mains and the power curve falls off. You may continue to go faster, but you aren't constantly building power. There is a point where you are just shoving gas through them for no benefit. The needle height comes into play here, but you need to get the right size mains first.
(See Factory Pro
- Product Support - Motorcycle Tuning Tech - CV Carb Tuning
I started with 200s to all four cylinders (I actually bought the bike this way). I use the UNI & Hindle full pipe. I felt it was pretty dialed in until I put it on the dyno and saw the power curve. I now running 165/170s, love the power band of the bike, and I can squeeze 50-55 MPG in the twisties all day. I liked the Factory Pro kit for various reasons, individual needles for inside/outside banks, reputation, customer support.