Well, I just wanted to share my story of water pump failure at 98,500mi. Of course I was on the interstate when I got the red overheating light. Symptoms I noticed were the heat went cold and the lower radiator hose was cold. No coolant leaks. Got it towed to a local shop so they could scan it (my scanner is generic and won't read BMW specific codes) and of course it had the water pump and thermostat failure along with the intake camshaft sensor failure-2A9A-this explains my long cranks at start up. The shop wanted $1,200 P+L. Called the stealership just to get another estimate and that was $2,000 P+L. Well, I have done all the maintanence on all my car and feel pretty mechanically inclined, so I decided to tackle it myself. Ordered my parts from oembimmerparts.com (Piersberg water pump, thermostat, coolant, and camshaft sensor totalling $580). I studied the Bentley Manual and forums and went for it once the parts came in. Well, low and behold, once I got the splashguard down, the electrical connector was disconnected for the water pump. Connected it, ran the car, and still overheated so the thermostat still failed shut. Went ahead and replaced the pump since I already had the part. A couple things I noted, although, the thermostat can be removed without removal of the pump, it is much simplier to remove the pump first because of the metal water line going from the pump to the engine block. It doesn't budge and I had to push up hard on the pump and the mounting grommets gave it enough slack to get the t-stat by also a few scrapped knuckles. The hard to reach water pump bolt was pretty easy to get off if you are positioned at the front of the engine and go in at an angle just in front of the wheel well. I used a 10" extension and swivel joint and of course the E12 socket for the bolts. I also removed the coolant resevoir after draining the coolant which helped with accessing the hose clamps on top of the thermostat. It took me about 3 hours total, that's not including my lunch break
Overall, it wasn't as bad as an experience that I thought it would be. Note, that I did have a garage and I used jackstands on all four corners. So there's my experience.