Okay, I tried out the Fly supermoto boot. I soaked them in Neat's foot oil a couple days prior to wearing them, cuz I knew they were going to be stiff. I'm not too sure it helped, because they were still really tough to break in. Since I am a relative newbie to dirt/moto, I had a little trouble getting a feel for the bike while wearing them. After a while, they did get a little softer, especially after knealing beside the bike in them a bit.
As for the riding, the sole really glides over pavement nicely. I was surprised, though, that it wore down really quickly. I didn't think I was applying much pressure to my foot, but I wore the outside of the heel pretty bad. Still, it had a good feeling for the traction, and was a good speed gauge. As was questioned before, I tried using the ball of my foot while in the corner, and my pegs gripped the soles well. Nice feeling there. My pegs aren't especially sharp, just normal I suppose.
Overall, I'd say they are a nice moto boot, if only I could break them in better. Looking at www.flyracing.com
doesn't give any insight to how difficult the soles are to change, nor does it list the sole as a replacement part. I know my dealer told me they were available. I'd give this boot a B+ for style, concept, and purpose. It would grade higher if it had softer leather.