Spark plug NGK or OEM FORD

NGK is prob the best sparkplug for performance, Denzo is a cheaper option but there not as good for performance

If you live some where hot, have a tune, or are hard on the car I would do one colder and get the 2309 instead of the stock 7913.

Any correct sized , heat range and gapped NGK plug will work fine but some will need to be changed more often. BKR6EIX for example is a good choice, it is iridium tipped and not expensive.

Always stick with NGK. However, NGK has different lines from copper, to platinum, and iridium. Iridium is more expensive, but will last longer. Given they're a bit of a PITA to replace, I'd go with these. I've run them in my 2004 WRX the last 8 years.

if the car isn’t stock and has been tuned, you’ll want to follow the recommendations of your tuner/just put NGKs in it.

Car is very picky about spark plugs because it uses the spark plugs as knock sensors, I used basic NGK copper plugs and replaced every 10k. Very easy to do.

Just changed my spark plugs.. went from 031/032 factory NGK1675 gap down to 027/028 gap (based on the feeler leaf gauge). i am here to state beyond shadow of a doubt that 027/028 gap feels way better. The car is smooth.. so smooth in fact that it makes me feel like the CEL is about to come on. In 7 years of ownership, I never felt it as smooth as it feels now. When idling I almost feel as its off.. also at speed!

Got new NGK BKR8EIX pugs today and gapped them to 0.024". Originally, 0.030" according to my gauge. Very surprised when I removed the old plugs as they were all at varying degrees of tightness even though they were originally torqued to 25NM. Car runs great with the new plugs. No complaints so far.

For a stock 4.3 you won’t see any performance difference regardless of what you put in there. Cheap copper plugs will work great but your going to be replacing them every 25-30,000 miles, iridium will probably last as long as the rest of the vehicle.

I put in NGK PFR7S8EG plugs and man the car ran like absolute CRAP when it was cold. It ran fine, even great when it warmed up but it was so bad when cold that it was virtually un-driveable especially under moderate or hard throttle. I ended up putting the old plugs (Bosch platinum/iridium) back in because it was so bad.