picking up a 89 760 turbo, have a few questions..

water pump leaks, I can find a cheap replacment, but is it hard to do?

the AC light on the climate controls steadily blinks.

SRS light is on.

Seems to like to stall at random occasions. It wont do it often, like once every couple of days or so, and you can immediately start it back up again. I personally never witnessed the stalling, so I am not sure.

and last what type of lubrication should I use on the sunroof?

-Thanks!