spark plugs

Champion N9Y............I thought these fitted all cars.............they did when I was a lad.

Depends on the car. Some run great with fancy plugs, some run worse.

If the manual recommends NGK that's what I'd use absent overwhelming empirical evidence to the contrary.

I put NGK's in my 520i years ago and it ran rough. Changed for Bosch and it was fine. Latest ones have 4 outside terminals coming up like arches and you don't need to gap them. They work well. They were $10 Australian each- probably $5 US.- everything is roughly half over there.

I used to second guess the engineers and try to do different things with my plugs. I've decided that the engineers know better than I, and now I select exact replacements for my plugs. I might go for Platinum, but I always select the single-electrode plugs if that is what my car came with.

I once bought a set ot plugs from the catalog, then went home and installed them. The car ran like s*it, and took me hours to trouble shoot. I could barely drive it to the shop where they put it on the scope. It turns out that my factory plugs were something like 123C-xxs, and the replacement plugs were 123-xxs. The "C" was a very important character -- it meant that the plug was the "high output" type instead of the standard type. Now, I pull a plug, and drive a different car to go buy more just like it.