Just FYI: Miatas have the exact same problem with their plastic radiator end tanks. At 100k, it would not surprise me to see a non-original radiator on a Miata.
And I had the fan explode on my Toyota pickup. The difference there is that it's cool to have a fan shrapnel hole in your hood on an old Toyota pickup.
I'll probably do the water pump on my M5 this summer ($350, sigh) and I might look into building a shroud for a couple of electric fans at the same time. Just because I like electric fans.
