[clickman]

To the OP, if your car is a 99 and the water pump has never been changed, do it now. They're plastic and time in service, not mileage, is the critical factor. And if it blows, imagine trying to get all the little pieces out of your engine and coolant system. Small bits in the tiny head passages = cracked head. No thanks.

Replace the pump, your front motor mount is also likely due, and it's worth it to do the 160 thermo at the same time. And the belt for sure if it's been a while.

I also replaced the smaller oil cooler on my base Boxster for the larger S unit.

Those that recommend the venturi vacuum system are right; it makes the coolant replacement a breeze.