There was a recent thread on this question. Consensus is that there is perhaps a small improvement, but probably not worth the extra money.

I agree with the response above - it was very irresponsible of your shop not to change all of the coil packs at the same time they had everything apart to get to the plugs and found a bad one. I recently had a coil pack go bad, and had the same symptoms you had. We never considered changing only the one bad one.