FYI, if you're looking for a 170mm crank with standard rings then RBP has 10 speed 105's on sale for $135. Crank and BB will drop about a quarter pound off your bike and match your 105 components. I personally would rather have that than carbon cranks. I bought an FSA Energy crankset from them a couple of weeks ago, they ship really fast.

SHIMANO 105 FC-5700 170mm 53/39T Road Bike Crankset + BB Double Black | Random Bike Parts