how does one remove and replace the shift knob on a clk 500 and what aftermarket knobs are available for the car

 

No idea on how to take the knob off but as for available gear knobs on the market, Momo will be one of the most common ones, they can be fitted on any make of cars, they have a universal fitment in their design, or you can always try Brabus, Carlsson, Lorinser or AMG for go with the Merc.