Try and figure out how much of the bits remain in the system. Look at what you've recovered versus what an intact pump impeller looks like. Worst case would be there are so many bits that coolant flow is impeded, resulting in overheating.
Another case would be that the bits do not become lodged, but rather circulate, and break your fancy new water pump.
But if the bits in your system are few and small, I would not spend much more time or effort dealing with this, such as tearing down the engine to clean the coolant passage ways.
As a last ditch effort, you can drain your coolant, save it, then hook up a garden hose to your cooling system and try and get as much water pressure flowing thru the system in the hopes that the bits will dislodge and exit.
I am in Vancouver as well. Doesn't driving a porsche make you hate the city for having such terrible roads? I wish I lived in Florida