I currently have a cadd 8 with full dura ace, and a six13 with a 105 and ultegra mix and a sram rival crank both bikes are 08, just want some real opions if it makes any sense to spend The time and money to move the dura ace to the six13 or if I should just countiue to ride the bikes as they are, and if so which would you say is the better bike.