I have a few questions. First, would it be beneficial to my Z to put in 104 plus octane boost in my tank when I fill up? Second, what are the best spark plugs to put in, or are the factory ones best, Third, will either void my warranty. thanks

just putting in higher octane gas and changing the spark plugs is not going to void your warranty...if your car is completely stock..i dont know how beneficial putting in 104 octane gas is going to be...besides slightly better gas mileage maybe...

Being a nissan tech, the octane boost would be a waste of money and the factory plugs are the best