Wheel upgrade question

[Dombo]

Need some advice. Bike came with pretty standard Bontrager Race wheels. The Race X-Lites are on sale at 40% off with E***s, and seem to be much lighter, more expensive (=better?).

Would upgrading to these wheels make much of a difference? Bike concerned is the orange/black carbon Lemond sometimes seen desperately hanging onto the back of the CR 18s.

Sitting at my desk thinking about it I imagine they'll make a huge differnece. Would they in reality though? Any advice most welcomed.