Performance difference between Shimano SPD and SPD SL Is there a noticable performance different between the SPD and the SPD SL systems?  I've got SPD SLs on my current bike, but some of the touring I do required quite a lot of walking, so I was thinking of getting some SPD pedals so I could use shoes that were easier to walk in.  

My current shoes are racing shoes - exposed cleats - but they will take SPD cleats in it.  So if I swap them over, will the ride be particualrily different?  Or should I keep them SPD SL and just swap over the pedals whenever I want to use them (as I find them very comfortable with the rigid sole).  

Thanks
There likely isn't much difference in performance. Some people do find that SPD cleats lead to "hot spots" (painful spots) on the balls of the feet; that's why I went to SPD-SLs. 

You might find a difference in platform height; IIRC the height of the SPD cleats + pedals is shorter than the SPD-SL. You'd want to adjust your seat height to deal with that.