well........I am going to the 3.4 but I will need some more flow, otherwise I will be knocking quite a bit. I have a hard time believing that all of the people here who stated that they saw vehicles with cracked plog's or have had them crack on their own vehicles had these issues from having a turbo. I agree that if you had a turbo it could put extra stress on it, but most people in this thread do not have turbo's...