Water pump OEM Audi or OEM Toyota

My waterpump developed a crack 3 weeks ago and I started to leak coolant. Car had 20,000km on it. Had it all replaced under warranty. Was open about the mods on the car as well and dealership didn't give me any issues.

Waterpump failure at 26k factory installed (plastic impeller, bearing)

Not true. The maintenance schedule for the belt is 105,000 miles. Many of the pumps with plastic impellers fail before that. The plastic composite seems to age and become brittle after 70k or 80k miles--some sooner and some later. But they do fail. This is what happens: