1 Cleats aren't compatible with other models according to the website,
they all look different. I don't know if it's actually possible.

2 I'm using X/2 right now, got a deal and upgraded from X/5. I wish I
got the Zero's to play with the float adjustment. Sometime when I'm
off the saddle, my heel strikes the chain stay.

http://www.youtube.com/watch?v=b-rQN...6zPoymgKaIoDLA