help with diagnosis on 2000 boxster s

[Rich XTR]

I have a 2000 boxster s with 53,000 miles. I haven't had it very long and don't know the service history. I could use some help diagnosing a problem. Here are the symptoms:
[*]had a check engine light code P1341. I reset it and it came back after 20 miles or less[*]the engine has a rattle at start up that last just a second or two[*]i found lots of green bits of rubber in the oil filter[*]durametric cam deviation is -7% bank one and -10% bank 2. both are solid and unchanging. also cam timing is 1 deg up to 2500 or 3000 and then changes to 25deg on both banks
Car runs very well.

After researching it sounds to me like one or both chain tensioners for the variocam is/are toast.

Any input would be appreciated. Thanks