As an owner of a 08 R3 with SRAM Red/Force any of the top groupsets will make for a great build. If I were in your shoes I'd just go with the one that you like the ergonomics of and then move on with the build. An R3 is meant to be ridden and enjoyed.

Mine, even at 61cm and with ZIPP 404 Max Clinchers, weighs in at 15.2 lbs with computer, cages etc. They are great bikes.