986s Squeaking at idle.. Light Hissing.. Oil cap stuck on.. AOS?
 

2000 Boxster S (3.2)
6 Speed
77,000 Miles

Last week I noticed an issue that my 2000 Boxster S was beginning to make a squeaking noise at startup. It would squeak for a minute or two and then stop. I assumed I was looking at an issue with a waterpump or a bad pulley, and figured I would start digging into the issue this weekend.

Today (first time since I first noticed the squeak) I decided to drive the Boxster about 10 miles to the office and see if I still had a squeak. I did, but this time I noticed that it was constant at idle. I turned around to limp the car home and further investigate.

Symptoms are:
* Aforementioned squeak at idle, which now seems intermittent again.
* Oil cap is impossible to remove without tools with the car running.
* For the briefest of moments I saw an oil pressure light flash at idle while troubleshooting.

Everything I have read online seems to point to the AOS, but I don't have an abnormal amount of smoke at startup. Is this common? Are there any other ways to troubleshoot the AOS before throwing parts at the problem? Are there any other parts that I should order in addition to the AOS? I've read on some other posts that it's a good idea to replace the oil fill tube at the same time because it has been stressed by the vacuum created by the failed AOS?

Any additional tips/tricks to performing the replacement would also be greatly appreciated.

Thanks,
Hammer