carbon fiber chassis and a arms for savage do look cool! you can't argue with that they're so..... something!
strength:
aluminum<titanium<carbon fiber
lightness:
aluminum<titanium<carbon fiber

don't flame me if I'm wrong on any of these...
also even if aluminum is lighter than titanium you need more material to achieve comparable strenght
in other words aluminum stuff will have to be thicker than titanium stuff to boost strength