Spark plug Bosch or OEM Mazda

I have a shelf of new parts for a bunch of my VW’s. All the cap and rotor parts I can find are the same for either car. They’re brand new. The plugs are brand new as well. Gapped by the Bentley. The plugs were “black” from trying to fire but not.

I purchased from a local auto parts store for my 07 E550 and SO's 05 E55 - stealership quoted around $1k, parts for each with Bosch Iridium plugs was about $125. Installed new plugs at around 70k for the E550 and OE plugs (also Bosch) looked clean and the gaps were spot-on

I had those on my 2017 civic 1.5t sedan that I had some performance mods done to and they worked great

So I decided to I replaced my spark plugs. There was a ton of carbon build up in the first cylinder, and oil on the 2nd, 3rd and 4th spark cylinders, including the spark plugs. It’s running way smoother now but there is still some jerking but it’s not as violent as before.

I am running LiquiMoly Molygen at the moment, use LiquiMoly Engine Flush and Direct Injection Cleaner when chaining oil, put in new Bosch plugs and coil packs about 9 months ago.

They're both fine brands, I doubt you'll notice a difference. NGK is most likely OEM for your Civic, but it's not like Bosch is bad, they're OEM in my BMW.

The Neuspeed chips don't perform well at all, and the 2.0's do best with BOSCH FR8DS's.

Although I prefer Bosch sensors over other brands in certain parts of my Mk 5 2.5, I will not buy Bosch spark plugs. Many professional mechanics over the last 3 decades have told me horror stories about them.

Warning about Bosch spark plugs!!! The piece of ceramic around the electrode failed. These were in a 2018 sonata turbo for about 10k miles. Thank God it didn't fall in...

Ive used bosch irridium plugs as replacement for the original denso ones in my GFs 2015 yaris and the car started to have misfires (noticable shuddering) within a couple of weeks. The bosch part is listed as compatible with the OE number, but issues nonetheless. I'm currently going through the warranty process and definately wont be using anything other than the direct denso replacement.