Have had a CEL (NON-flashing) on and off for awhile.  3000 miles ago (when the car had 48K miles), I took it in to a local Porsche place.  The guy did diagnostics on it, which indicated "misfire, cylinder 1".  He said it was very short-lived, could have been due to any number of innocuous reasons, and said I shouldn't worry.  He reset the CEL and recommended "drive her hard" on the way home.  I did, and everything's been fine since...until yesterday.
CEL returned, and I went back.  Durametric readout again indicated "misfire, cylinder 1".  The mechanic said it had occurred three times, all at very low RPMs (eg 700 RPM)---he seemed to think it occurred when I was cranking her, ie before the engine had really even started.  He again seemed to think there was nothing to worry about, that I could probably go until the 60K maintenance to have it checked out, but also said I could pull the spark plug and take a look if I was curious.  He reset the CEL and I went on my way.  The 20-mile trip home was fine, no issues.  However, I shut the car down at home, then went out like half an hour later and drove off.  Got maybe 1/4 mile and she started missing noticeably, especially at low RPMs.  I hobbled home and decided to pull the cylinder 1 spark plug.
Did so.  As far as I can tell, the plug looks OK.  I'm kind of a newbie when it comes to Boxster mechanics, so I'm really not sure.  Anybody have any insight here?
 
   
Assuming the plug is OK, what would my next move be?  If I take the coil pack and the spark plug in to a dealership, could they test the coil pack for me (as well as assessing the plug)?  I haven't pulled the spark plug well (tube), but (inserting a clean finger in there) it seems to be clean and without any obvious issues.
What should I do next?