Depends. I for one love the Carbon Fiber Roof and think it's well worth it. I saw a Velocity Yellow with the Z51 package at Carlisle this past summer with black wheels, Carbon Colored mirrors and spoiler and the Carbon Fiber Dash. The Carbon Fiber roof was the exclamation point for me. All together that combo was incredible. I knew in an instant that my was exact combo.
Of course it all depends on what you can afford. If the extra 2K is a stretch then put it towards something else like others are suggesting. If you can afford it and like it then I say do it. Is it practical? No. But then neither is buying a Corvette.
Do what makes you happy! I for one will be ordering it.