Hi Wallis... Guru made a model called "Racelite" which used that exact combination. (Maybe you are buying a Guru?). Anyway, I rode one for a season and it is the BEST Crit bike you can have. Really stiff and responsive... However, if you are going to ride or race 100miles on bumpy roads, you will feel it the next day, BIG TIME. If you ride on mostly smooth roads, this is a fantastic combination of tube and carbon usage. And, as you stated, it is pretty light!
Rocket69