After replacing my vacuum hoses, I was able to reduce my idle some. I ignored my vacuum elbows because I thought they looked good. I pulled one and there was a very small crack that was not noticeable until you removed it and squeezed it. Replaced it and my idle issue has been solved. Don't ignore those elbows!
http://www.autoatlanta.com/Porsche-Standar...R022129637.html