Got myself a 95 C140 and have some questions

[kanio]

I finally bite the bullet and got myself a 95 S500 coupe. Man, what a luxuray vehicle. I am learning to drive it both smoothly and agressively. Like all used vehicle, the car need some minor tweaking and fixing. I got some questions and hope to get answers here.

Problem with the vehicle:
Radio Antenna not going up. Look like the motor is bad. Maybe Jim F's site on it is the fix.

SRS light stay on for a few minutes after I start the car. The mechanic told me it is the driver's seat belt buckle sensor need replacement. Is this a hard job?

The trunk close assist works, but I don't have close assist in either of the the door. Are they both broken, just didn't have that option?

I am also getting wind noise from the driver window. Are there any reseal kit for the door?

One of the headlamp wiper is not working, Is the motor bad? Is this a easy fix too?

The headliner is sagging in the back. Any easy fix here?

Thanks for your comment.