I've been installing plugs since the late 60s and tried most of them. The Bosch are one of the best I've used. On Turbocharged engines, they were one of few that weren't eaten alive. Jap plugs have long life/good performance. Motorcraft/Autolite do well too. I used to love Champions (back in the pre-emissions days) but all I install them in now are one lungers. I've been running +4s since they came out with no problems. I don't believe they are too much better than the factory fill. They do look cool though! :p
