Buying my first boxster

[Perfectlap]

I'm going to guess that between keeping an imsb and the original water pump in for too long the water pump failure has claimed many more engines or forced a rebuild.

You should update the coolant cap to the 2004 revision which I think is the most recent. This should be part of the pre purchase inspection in my opinion. You don't want to flush the coolant, replace the water pump or the replace the troublesome coolant tank without also updating the cap. It's a $20 part that can throw a wrench to the entire cooling system.