[edc]

Originally Posted by Gelbster

If you buy just the coolant cap ,the latest part number ending "00" is the best according to other Forum members.I have been unable to find a part number on my cap.
The latest listing I found is for : 996-106-447-04
2001 Porsche Boxster S Convertible - Radiators - Page 2
This may help you:
Porsche Boxster Coolant Tank Replacement - 986 / 987 (1997-08) - Pelican Parts Technical Article

The latest part number is 04 and if you buy a genuine one the number is on the top!