Spark plug Bosch or OEM Toyota

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

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.

I have an 02 4runner with 289,500 miles. I've had it for the last 106,000. Replaced the timing belt/ water pump twice. Replaced spark plugs twice. New brakes a few times.

I used Bosch iridium spark plugs in my 2018, no issues

I recently just replaced my spark plugs they were past due. So I bought the OE Bosch 9683. The engine runs fine, starts easy, no misfiring, no rough running. But after the plug change I am getting much worse millage.

Also, some engines get particular about plugs. Bosch has a bad rep for the 3400 engine in my Grand Am, while NGK and AC Delco(I've got NGK Iridium IXs in there now) are fine.

I think I just went back and got the Bosch. Couldn’t return either because I jacked up the nips trying to tweak them off ????

Champion is OEM and what we suggest at work, but NGK has never failed us with any application. Bosch is generally terrible and we only use them if it’s a very specific application.

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.