Well I picked up the new oil cap today from the dealership for $19 and was pretty excited, but it hasn't fixed my hunt for idle issue. I will say though, that this thing is drastically different than my old cap (yellowish), so I'm glad I got the revised cap anyway. Was a fairly inexpensive excuse to go visit Courtney at the dealership
(side note: I have a theory that there is at least one Courtney at every Porsche dealership.. Austin? check. San Antonio? check.)
The "hunt" continues (no pun intended)...