My commuter has 105 components. They're pretty nice. Every now and then it'll be a bit sluggish when I shift in the front, but I have a double chainring, and my shifters seem to be made for a triple. (?) That's really the only complaint I've had about them.

Does the carbon bike not fit you, or have structural damage? It'd be a little odd to cannibalize one for parts!

The gearing is a bit low on this, though. If you have any significant hills in your neck of the woods, you might wind up buying a new cassette ( which is like $35 for this group ).