I've heard other people have had bad experiences with Bosch plugs. Here's mine: About 6 months ago I bought a set of the bosch platinum +4 plugs and ultra premium wires and paid about $150. The car ran fine at first but about 15,000 miles later the engine started to miss every so often under low throttle. The problem slowly started to get worse. My cougar ran like ****, especially when cold. I talked to a guy at Five Star Ford and he said that you can't use Bosch plugs in any Ford vehicle. Although I know he was trying to sell me a set of plugs, is there any truth to this statement? I decided to just swap the plugs with NGK's. The engine hasn't missed since and it idle's noticeably smoother. What's the story on these Bosch plugs?