sharing my experiences w/ '94 E320 coupe (105k):

>had monobelt and tensioner changed 2 times since 60k

> haven't needed h20 pump- (knock on wood) - - yet. You can verify the relative condition of the h2o pump by listening to it with the motor running w/ a mechanics stethescope (might as well also listen to the air pump and pulleys, etc. too)

>$65/hr labor rate is a bargain!!!, here in SF Bay Area at fact author service its over $100/hr

hope this helps
-fad