Yea its really strange. I like the kit and price enough that I'd consider flipping it for a 19...but 23.8" still seems like a generous amount of (effective) top tube. I wouldn't dare go any smaller with them though since the smaller head tubes are bound to leave me with the bars too low. In retrospect I really wonder what Trek's design philosophy was with these...

On the other hand the Cannondale's 23.0" TT (on the "L") seems like a dramatic change, and of course my fear will now be overdoing it and going too small. Heaven help me.

For what its worth my previous bike of 5 years was a 08 Giant Rincon (with 23.3" of TT and more than 6" of HT). There was nothing wrong with it except that I wanted to go faster on the commutes and weekend trail bike-hikes...which the DS certainly delivered on....in spades.