The bottom bracket height is something you can't change. It's deliberately low. Trek have made it low 'for stability', they say. On corners, they may have a point; in a straight line, like what you do in time trials most of the time, I've not found that bottom bracket height makes a difference, even on the tri bars. The other effect of lowering the bottom bracket height is that it lowers the saddle height, and reduces the drop from saddle to handlebar, by the same amount. Result: you sit that much more upright.