As for daily driven cars, since when has a lighter vehicle not been a benefit???!!! Ever driven a car that felt a little sluggish after filling the tank up with fuel or added a passenger or two? The performance aspect isn't the main benefit as much as gas mileage...

The problem is the current cost of carbon fiber and the additional labor to create it is [probably] not less than the gas saving acquired...in the long run i'm sure it is though. Ford build a carbon fiber Crown Victoria/LTD back in the 80's that saved nearly a ton of weight but it cost $250k to manufacturer, lolol.