If you have any sign or history of any oil leak in the vicinity of the spark plug area, I would consider replacing the spark plug tube o-rings "while you are at" replacing the spark plugs. There are two o-rings per tube, and even genuine Porsche parts here are not very expensive. The spark plug tubes will be accessible when you have the coils removed to replace the spark plugs.
Spark plug tubes
As for the coils themselves, as I demonstrate in above-linked post, I would recommend cleaning their exteriors, and giving them a very careful inspection them when you are changing the plugs. Be on the lookout for any cracks. All six of the coils on my 120k mile, 2001 2.7 looked perfect and wouldn't be able to be distinguished from brand new coils after being cleaned up, (with the exception of a couple of the the silicone rubber boots having small tears - available separately as Porsche part number 996-602-105-00).