i've wondered this myself.

i have a synapse alloy and, when comparing the geometry charts of the synapse alloy vs. caad 10 on the cannondale website, they really don't seem to be that different (we're talking fractions of centimeters and degrees). from the numbers, it seems like the synapse should be just as raceable as the caad10. most of the "plushness" comes from the shape of the stays, i think.