One of the small trailers (for instance:
http://www.harborfreight.com/cpi/ctaf/Displayitem.taf?itemnumber=42708 ) completely set up and with a set of track tires on it would probably weigh in at ~220 pounds.
Comparing that additional load to either carrying "larger" passengers, several large full suitcases or just making many quick starts, I don't think the additional wear on the car would be an issue.
Would Porsche raise an issue re: warranty if you drove in with the trailer attached and claimed early engine failure, etc...? Certainly. The hitch design shown above is completely removable so they will never need to know.
