Spark plug replacement on 5.4L V8
I've got a '99 F150 with just shy of 60k miles on it. I'm pretty sure the spark plugs need to be replaced as it was running roughly and gave the P0304 code yesterday for cylinder 4 misfire.
It looks like a PITA to change myself, so I took it to a mechanic. All was fine until they called me back and said they had made an error and that the plugs were $18 per spark plug. They're suggesting that the only plug I can use is the NGK 6579 plug. I called Pep Boys and Autozone and Kragen who all suggested Autolite Extreme Performance plugs that run around $6 instead. Who should I trust??? I need to make a decision soon as the truck is at the mechanics right now (although I asked them to hold off until I decide what to do). Thanks!!