Not usre how the Trek 2.3 is but when I upgraded from my Specialized Allez to a no name chinese carbon bike it was a world of difference, night and day. On long rides the road buzz from the aluminum Allez would kill me, especially my hands and feet! But switching to carbon made such a huge difference. I wasn't tired and beat up after long rides anymore. So if you can swap to a carbon bike and it's within your budget, I'd say got for it.

I still have my Allez but I use it on my trainer or my wife uses it once in a while.