Problems with the secondary air system are fairly common and most often it is one of the vacuum hoses that has cracked or become disconnected. The most expensive part that could be a problem is the blower (secondary air injection pump), which *can* cost over $500 new.
The system itself only operates during a cold start to clean emissions by providing more air to the exhaust for more complete combustion. It does not effect the performance of the car and was not even installed on cars marketed outside North America.
Not a big deal to have the Secondary air system fail, but a minor vacuum leak may lead to other problems. The other consideration is in some states it will cause you to fail an emissions test.
If it were me, I'd take it back to the dealer when I had time (during the warranty period) just to be sure. 100 miles... that should take just under an hour to drive right?
A dealer or import mechanic that does not normally work on Porsches may have a hard time tracking it down properly.