I would get onto the dealer and tell them not to waste your time and to replace the lot. When one goes the others are often not far behind. It is not incommon for these to fail so not something to be overly concerned about.
Also I believe putting a new coil in that is not matched to the others may shorten the life of the remaining coils. Get the dealer to replace the others under warranty.
If you do tune the car I'd upgrade them along with the tune.