I don't know...the high-quality plastic system that is engineered by the MB people is very delicate (and expensive to renew). Personally I always prefer to see what I am doing and therefore take off the rear panel.
The power system for adjusting the headrests is just simple, easy to crack plastic and as soon as one little plastic part is broken, you need to buy the complete system to get the headrest going again.

greetingz,

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1990 300SL-24
1993 C250D with a minor 600+k kilometer
www.MBenzNL.com(the Netherlands)