I totally agree with everyone above. The price difference is small and worth upgrading to carbon. I am pretty sure that if you don't buy the carbon, after 1 year, you will want to upgrade to a carbon frame. A Giant carbon 105 for $1599 is a good deal. See if your bike shop can throw in a bike fit too.
2014 Liv Lust
2013 Specialized Fate Expert with carbon wheelset (sold)
2012 Specialized Amira Elite
2010 Santa Cruz Juliana with R kit and Crampon pedals (sold)
2011 Specialized Ariel Sport,suspension post,Serfas Rx Women's Microfiber saddle (sold)