Rollie- I was in the same boat and opted for the 105 and carbon instead of Alum/Carbon fork and Ultegra. I do have the Ultegra rear deraileur. Anyway, my bike shifts very smooth and I am happy. Would full Ultegra be better? Probably. Am I disappointed in my decision? Not at all. My old bike was Sora, so this is a nice upgrade for me. As parts wear out or budget allows I will eventually make her full Ultegra. I love my carbon frame though .