I would like to know which spark plug would be better. I am looking to replace the plugs on a ford fusion. They have autolite iridiums for 7 bucks which they have in stock. They also have motorcraft for 8 bucks which they would have to special order and they also have NGK for 14 bucks which it says is oem. Are autolites any good. They didn't say how long the service life of the plug is while the motorcraft says 100k. The car presently has 97k on it and i would like to do this as soon as possible. Thanks in advance for any help or input you guys can give me.