My Giant Defy Advanced has a CF teardrop shaped seatpost for an 'aero' advantage. Of course I usually have a big seat bag hanging behind it disturbing whatever area advantage there is.
I had to buy a $35 adapter kit from Giant so that I could use my workstand on the post.
Then like a big dummy I managed to over-torque the seat post clamp and ruin the seatpost. Instead of just buying any 27.2 post, I had to special order the teardrop shaped post for $200. I also bought a small torque wrench and some Tacx Carbon Prep so I won't make that mistake again.