You can also get the "lower" Amira Elite and upgrade your wheelset instead of buying the Amira SL4.
I chose the Amira over the Ruby because my back felt kinda hunched over on the Ruby. I felt that I had better handling with the Amira. I did not feel any difference in plush riding of the Ruby compared to the Amira. Even though I am 5ft1in with short legs, my long torso preferred the 48cm Amira.
As to carbon stiffness of the frames, 11R has stiffer carbon than the 8R. Thus, 11R can translate your pedaling speed to your bike better than the 8R (which, of course, also means that your 11R bike will be a little "twitchier"). Although I did not test ride the more expensive Amiras (due to my lower budget), the Specialized sales representatives said that the 11R carbon is stiff laterally but still compliant vertically....which means that although the 11R is stiff for pedaling strength, it should still NOT cause a harsh ride.
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)