Hodan, Hodan, hodan,... You are not going to take the advice that everyone has been giving you to buy a genuine Porsche tank. I understand, it's a lot of money.
If you are considering buying a USED one from 1999 for $150, please spend a little more and get this one from Pelican Parts:
Coolant Expansion Tank 99610614708Y - OE Supplier - 996-106-147-08-Y-INT | Pelican Parts
It is made by a Porsche OE supplier. There is a good chance that it is exactly like the ones originally installed by Porsche, but without the Porsche brand (and extra mark-up).