Spark plug Bosch or OEM Subaru

I have only used Bosch plugs in my cars, and I have not had any issues with them yet.

Changing my sparkplugs for the first time (32k miles, yes it's early but I got a great deal on the plugs) and found that the stock plug in cylinder 4 actually had a ground electrode defect and was significantly thicker than normal. The car runs stronger than it ever has as this was likely causing extra timing pull.

Bosch iridiums, these for longevity, copper ones have better spark if your concern is performance

Today I installed new spark plugs and the misfiring situation has improved significantly but is not completely gone. If I pull up the RPM too quickly the misfire counter goes up.

im at 95k with the original plugs. no issues

Just got a Jetta again - 2010 Limited Edition just shy of 100K miles and I've got one problem with it. From a cold start, usually in the morning, the 1st 10-15 seconds run rough before settling down to idle.

I have never seen any real large difference in NGK, Denso, and Champion if the proper heat range/type plug was used.

I'm not a fan of the old platinum Bosch design or regular autolite.

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.