Spark plug Denso or OEM Subaru

Hondas are notoriously picky about the plugs being Denso.

I’ve used denso IK20TT in whiteblocks and they work very well, may need to re gap if you have some boost raising shenanigans going on

I've never had any issues with Denso plugs, so I recommend those :)

Yes definitely get the original OEM Denso plugs and be really cautious of anything you purchase off Amazon a lot of them are counterfeits. You can either go direct to the Toyota dealer or you can go to your local parts store like Napa and just make sure you order the correct Denso Plug.

The plugs look really good pretty even color across all of them no major carbon buildup. Wear on the plug seems typical for 100,000 miles.

I've been running Denso IKH24 for 10k miles, have to swap them often but they've been great so far. Frequent changing will prevent damage to them seeing as they are normal projected grounds, but they are pretty cheap to replace once a year or so.

I run [Denso 5749](https://www.densoproducts.com/denso-5749-ikh01-24-iridium-racing-plug) non projected tip plugs with my FBO IS38 car.

They're 1 step colder, and non projected so the risk of a strap breaking off [\(like this\)](https://i.imgur.com/gdJFaJ4.jpeg) are extremely rare.

Denso or Bosh are the best you can return and get new ones

My 2010 came with denso, replaced them with ngk at 100k, then at 200k replaced them with denso…not sure if it made a difference

Yes! I had a set of iridium spark plugs bought off Amazon that were counterfeit! They were denso but I didn’t discover it till about 40k miles later when I had a misfire. Pulled plugs and they were toast… first set lasted 120k and looked fine..

I tried Denso once and didn't have great luck with them.