Hi
Orthopedic seats are not massage seats, they are simply air bladders fitted in the seat cushions that get inflated to suit the person in the seat.
They can be retro fitted to your seats, there is actually a WIS work instruction to do this, you will have to run vacuum pipe from the boot to each seat and fit a plastic air tank as well, you may also have to replace the PSE pump and possibly modify some wiring, but this will depend on the original spec of your vehicle.
It maybe better to get the complete seat with the air bladders and controllers already fitted, this is what I did to my C230k, and as the CLK is built on the same floor pan and chassis it shares many parts with the C class and the procedure will be the same.