So, I've finally given up on the K4 600. The frame and tank are just too damn wide for my shit hips (cam-impingement on both sides). The impingement doesn't affect other aspects of my life, so surgery is off the table for now. I rode a buddy's Ninja 400 on my last track day that had stock rearsets, and it was by far the most comfortable and confident I've been on track in a long time. After comparing the ergos side-by-side - which were roughly the same - I picked up a prepped Ninja 300. While I'm sticking with the 300 for a while, I was curious what other motorcycles might fit the bill for me. Narrow tank/frame are a must. I sat on a '15 Super Duke, and was blown away by how narrow the tank was on that bike. The RC8R seems like it'd fit the bill as well. What else should I look out for in the future? Seems like singles/parallel twins/V-twins are a good starting point.