Alec, thanks for catching my typo. XCS is indeed making the 1.75" post.
Alex, physics requires a smaller post will be slightly less rigid, but a wound carbon fiber post will be significantly stiffer than an aluminum 1.5" post. XCS does not compromise quality. Greg Bubb can give you the exact specs on stiffness for the 1.75" post. It's the only way to mount a M2 Volt gimbal on an XCS post. Like many, I've waited for someone to make a 2" version of the Volt, because I didn't want to give up my XCS post. The XCS solution of making a 1.75" post is a simple, yet elegant solution. I think it's the best, most rigid setup for a Volt available.