At 5600 miles, I recently developed the click feeling under my butt. I don't feel like the seat is moving, but there is definitely something going on with it around turns. Reading through this and seeing someone mention something about the seat height being all the way up, I lowered the front part of my seat for the drive home. Note I only have the front part of the seat up to provide under leg support, I only lowered it a tiny bit and the click was gone for my entire drive home. If it returns I'll do the same hose clamp trick everyone is using.
Also I notice my seat creaks when I push on it, but it sounds more like paper is underneath the leather. It sounds like paper is crunching, but it's only when I push down on the seat.