Took mine to the dealer for this code P0351, and the updated the ECM first thinking it was causing the code. Drove a little bit and bam the code was back immediately, took it back, they swapped the coils and no more issues. My mechanic seems to think that the connections became poor and were the cause of the code. I got 500 km on the update and coil swap and have tried my hardest to get it again before I leave for a big road trip, but no luck.
moral of story, I was certain it was a bad coil but knock on wood - "was an easy fix". I'll update should anything pop up. I have 54000 km. All stock.