I go Mobil 1 synthetic, only drive in the summer, seemingly done alright for the past several years. I recently changed stock plugs at 38K for NGK Iridium 1X, had a long road trip and have about 2K on them with no problems. Remember to use anti-seize if you replace plugs or you or the next owner will not be happy. No wires on the 12, they have coil on plugs. Don't see many people swapping coil packs. There are some upgrades, but cost to return seems pretty low.