[W126 Coupe] Power window motors

[Yousef]

Hey all 

I have been removing the interior + dashboard in order to do sound deadening, lay cables for audio system and replace vacuum pods ..

Anyways I've removed the door panels and I have a few questions.. 

1) my power windows are kinda slow goin up and down.. Could this be from old motors ? Does anyone know the specs on these motors and did anyone try replace them with better motors of some sort? 

2) between the glass sheet and the outter panel there is a sheet of some material.. What is it for and can I loose it since am gonna use the sound deadening material?

Thanks
Yousef

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