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.