6 Months ago I replaced my windshield washer pump because it was leaking all my fluid out. I did, what I have read, is what a lot of people do and used a readily available universal pump from my local auto chain. This pump was sufficient, but lacked power in its spray. It would reach about 1/2 to 2/3 up the windshield. It also made me use "taps" to connect it, as its connections and the BMW's electrical connections were different. Now, 6 months later, it is already having issues and my fluid all disappears again. i just bought a real replacement from my indie shop for $40 bucks! (online they are more than that). Anyway, long story short, this pump has MUCH more power in its spray, and should last as long as original (5-6 years) i just wanted to give my analysis here, so you all wouldn't make the same mistake. OEM is worth the money.
David