Thanks for this. It is useful. I have an S30 and have tried the S40 seat extension with the Adjustable CF seat. It seems to work OK, but I missed the use of a foam interface between the seat and the extension, so the interface is rough and somewhat stressful on the carbon parts. Can you please give some info on the foam you used, such as type and thickness (and even a source if there is one readily available)? Thanks again.