Spark plug Bosch or NGK

I like NGK’s. No longer have my E28 but in my 944 i still run NGK’s.

I suggest buying a known high quality replacement, not being picky about the exact spec, and seeing if that makes a difference. At under $5 it's a minimal cost and effort. Based on the what this engine was likely copied from, I would pick a NGK BPR4ES or BPR5ES from a vendor that doesn't have a reputation for NGK counterfeits.

I removed the Champion plug and replaced it with an NGK and on the first pull it ran.

I use NGK Iridium's in my generators. People say I'm nuts for spending the 10.00 for one, but I never have problems starting on gas or propane which is what I use with Iridium's, and plus you'll probably never have to replace it either.

I just replaced the stock plug in my Champion inverter with a NGK and it runs significantly better. No more random misfires.

I threw the nasty plug away, installed the NGK plug and it now starts on the first pull and runs smoothly.

I have always had luck with the NGK iridium plugs.

The car works almost fine with the new bosch , i have a little vibration on idling .

Plugs off if Amazon are fake, and they do some weird shit. We had a car in the shop that would shut down at random was due to fake plugs.

definitely avoid Bosch spark plugs. I'm not personally a fan and I've seen plenty fail. Unless they were original in the motor (usually Subarus don't use Bosch), I'd stick with NGK or Denso in my opinion.