One problem related to speed control cable has been reported for the 2010 Porsche Cayman. The most recently reported issues are listed below.
Shifter cable broke as I was entering the freeway leaving me without control of the transmission. As it was, I was stuck in first gear, but I could have been stuck out of gear, which would have been more dangerous. This appears to be a common problem and know defect to Porsche mechanics and many occurrences are posted on the internet. This is a safety issue, besides being a manufacturing defect.