Spark plug NGK or AC DELCO

I've run Denso and NGK on E85 for 10k+ miles and numerous track days, with zero issues.

Holy shit - $75 spark plugs? I think my Honda plugs cost like $5 a pop for NGK iridium

Also, you should probably go with NGK spark plugs because if you put Bosch ones that are made in China/Russia you are going to have a baaaad time

Some of those markups are insane. I can get NGK laser iridium plugs for less than $70.

At 85k I swapped to NGK Iridium Ix plugs on my 2019 civic with the 2.0na and I swear it added at least 20% response. Makes me wish I would have gotten it with a manual cause it would be so much more fun to drive around town. Also got a few more MPG

I just replaced all 4 spark plugs on my car @ 114k miles. Now I’m so glad I did it because the car feels way more peppy and responsive.

I upgraded to NGK Iridium spark plug in my classic 500, 2 years ago. There were minor but good changes in performance.

The fuel economy increased a bit and the self starts have been better.

We have tested a handful of plugs and wires (not the Chinese knock off stuff, but big name “Proformance” ones) and from a dyno stand point, looking at HP and TQ specifically… none of the wires out performed the stock AC Delco wires and the plugs all were real close to the same with AC Delco being close to the bottom and NGK being toward the top but negligible differences.

I changed my plugs for NGK IRs but now I have a rough idle when the engine warms up.

I had plugs from Amazon ngk and I had a wicked misfire couple days after. Somehow the ceramic broke off.