My 2011 4.5: When I bought it my LBS had some 2009 RXL wheels in stock and made me a good deal to trade up. Since then I've put on Dura Ace 180mm standard cranks, an Ultegra 12-23 cassette, Dura Ace chain, a Bontrager Affinity RL seat and R2 tires. Current weight is 17.7 lbs or 8,030 grams with Speedplay Zero pedals, cages, and Duotrap computer.