[A 986 S]

My car also has the transponder taped to the ignition switch. This works just fine and hasn't given me any issues. Do keep in mind that the owner's manual states "To avoid battery run-down, always remove the ignition key from the ignition lock." which suggests that there is an increased draw on the battery when the car senses the transponder. I make a point of connecting the battery to a maintainer when I'm not driving the Boxster regularly so this hasn't been a problem for me.

cheers - dj