Hi again. Thanks for all of your replies, especially pointing out the differences between the integrated (Cervelo) vs. non-integrated (my Trek) headsets and how this would affect the bar height. I don't believe Competitive Cyclist will ship to Hawaii. The shops in Hawaii have limited selections.

So, now I'm considering a trip to the US mainland to try to ride both a Cervelo R3 or RS in a 51 cm size.

Do any of you know of any bike shops in So. Calif. that might have a Cervelo R3 or RS in a size 51 cm?? Thanks so much (again)