I have searched around and I still have a few questions on going 1 step colder on the spark plugs or staying with the oem. It's on a 04 coupe, stock mainly. I get some pinging on the car and since I'm in cali, the gas is 91 octane and oxygenated (crapp). What are the disadvantages/advantages of me going 1 step colder here?

 

Stick with OEM unless you plan on going FI soon! It will richen you up if your NA

-sean