I put some in my 2010 around that same mileage and about 1200 miles after putting them in one of the ceramic insulators cracked causing a grounding problem leading to engine problems. I couldn't track down the problem so I ended up at the dealership and they found it. Replaced all 8 with AC Delco plugs and 30,000+ miles later it still runs great. By the way over that 1200 miles I tracked the fuel mileage carefully and didn't see any change in gas mileage or performance. In my opinion they are a huge waste of time and money. I didn't gain anything.
