Originally Posted By: nthach
Autolite is now 100% Mexican or Chinese made, the ones I've seen at Wal-Mart were Chinese for the coppers and Mexican for the rest. Bosch has been making plugs in India for a while.
I don't drive anything that uses Autolite or Champion from the factory - and while I do trust their OEM plugs(Motorcraft or ACDelco), the aftermarket ones might be made on a different production run or line. My instinct is NGK or Denso in almost anything.
NGK and Denso make the best spark plugs, and they are made in Japan or USA. Easily the best choice for any car, with very few exceptions.
Bosch spark plugs are good if the car came OE with them. Two cases in which Bosch is the best choice for cars that didn't come with them are Toyota's 1MZ, and the 5.4L 3V that Ford used on trucks from 10 years ago, with that stupid 2-piece design. Bosch makes iridium spark plugs for both applications, and they are made in Germany.
The 1MZ uses 2-prong plugs (NGK and Denso are both OEM for this engine) and is a transverse V6 that it's almost impossible to change them on, so iridium is a must since they last longer (so you won't have to do the job again for a long long time). So in this case, the Bosch Platinum Ir Fusion is the best choice since it's multi-prong iridium (it has 4 prongs rather than 2, which should be no problem)
And we all know about Ford and Autolite's stupid 2-piece spark plugs that always break. Champion's alternative is just as bad as the Autolites, and also made in Mexico like the Autolites. Both are platinum type as well. But now, Bosch makes iridium for them, making it easily the best choice for the 3V.
Some Volvos from the early 2000's came with Champion spark plugs, but Champion doesn't seem to make them anymore. They do make an iridium spark plug of the same type, but I'd still use NGK instead.
Also, for cars that use spark plug wires, NGK makes a great set that is numbered and a nice shade of blue