Before putting the K&N in, I took the stock air filter and cut out the restrictor and let the filter soak in detergent all night. The K&N was on the way anyhow, so if it ruined it, it wouldn't have mattered. The next night there was a layer of silt on the bottom of the container I let it soak in, but after thorough rinsing and drying, I don't feel this improved airflow at all. I modified the exhaust without making it louder, and with the smallest jet that I bought, 140, it was still slightly rich.
After putting the K&N in, I was able to go all the way to the biggest jet I bought, the 152.5, and it is ever so slightly rich I believe which is what I would prefer. With the unfortunate single clip position needle jet, I recommend doing a combination of both the
needle jet shim as well as the stuff recommended in the
power increase thread, move all the stock pieces on the needle to below the circlip and then what I did was add 2 more washers that are ever so slightly thinner to the suzuki washer. I would say it's about 2.5 "stock suzuki needle washers" between the circlip and the plastic ring. This was the richest I could go with no "jerking".
Part three of the power increase thread I'm finding very concerning. Stock is 1.75 turns out, and he claims that after his modification that he was at 2.25 turns out. I followed his instructions and turned out till the RPM maxed. This occurred distinctly at 5 turns out, not 5.25, not 4.75, a distinct peak at exactly 5, which should be really rich??? Not only does the RPM max at 5 turns out, but it doesn't have any signs of "stalling or doubts" and it drops right to idle RPMs beautifully. Any other settings and I see the symptoms he describes for being lean or rich.
The conclusion? It's as everyone says, a lot more confident in the low and mid range, not much effect on the high end, but it doesn't sound or feel like its going to vibrate in half at 65mph now, and i've hit 78 on huge downhills. So i've got a bike I can bring on the NY thruway now!
So tl;dr im perfectly dialed in after A LOT of work and it's surprisingly rich settings. Strongly recommend this mod to everyone, even non experts.