Spark plug NGK or OEM Mazda

After changing: Idles better and more consistent at 700~800 rpm range. Car drives smoother? Changing spark plugs made it visibly better.

NGKs are my go to’s

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

My RX8 also got pretty piss poor compression numbers. The only time it struggled with a start up was with literally the original 20 years old plugs it came with and I had to do multiple hot starts. It still started and carried on.

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

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

Please use original plugs for the replacements. Just yanked out aftermarket NGK platinums because of a misfire. For some reason, Mazda and aftermarket plugs in my experience always resulted in a misfire.