hm.. interested in this too! Have been looking at those specialized carbon soles for a while but haven't had the excuse/reason/moment of insanity to put down the $ for them.

btw, i do really like my specialized bg comps since they seem to fit my feet better than the sidis. they have a wider toe box which brings up a point. i don't know if the pros are the same but if you have narrow feet you might wanna try them on first to see if they might be too roomy for ya up front. fits my foot shape fine...

would love to hear if anyone has actually ridden them though.