Well, in that I'm now an "old pro" at doing water pumps (read as: did my first bimmer water pump yesterday), this is fairly straight forward, and I consider myself having only slightly above "novice" mechanical experience. Problem is, I'm not familiar with your particular motor.
I would advise you to follow the Bentley manual, and check out Bruno's site (bmwe34.net) for more information...between the two, this was a snap on my M30 motor. While you're doing this, might as well do your belts and hoses, too. Would also advise thorough and repeated bleeding of your cooling system once done.
Just my $.02 - if I can be of any help, pls let me know. Good luck!
Rgds,
Tim G.
'91 535iM