I replaced my pump after it starting leaking at the seals. This is relatively common. Got my pump for $68. Took 20 minutes to replace. No issue since. Rumor was that if you didn't use BMW windshield wiper fluid, this is common. I was running meth. The new pump had a different P/N than the old one and looked slightly different. I'm not sure if its improved or not.
'13 35i M-Sport X3 | JB4 Stage 1 | BMS Intake | H&R Springs | Gloss black grill | CF Wrap and Coded by me | Recaro Child Seats
'15 M3 DCT AW/SO | JB Stage 1 | RKP Diffuser | P3 | M Perf Spoiler | iND Exterior Trim | Recaro Child Seat