My 1992 9kt is mostly stock, and is running on a 2002 black DI from a 9-5. It has recently been brought to my attention that I may not be running the correct plugs for the car. The last time I changed them I went with NGK iridiums (I usually work on asian cars and these plugs are some of the best.) But I have heard multiple places that they produce too hot of a spark for my car and can cause hesitation and stumbling. I have not had any of these issues, but would like to run the best plug for the car anyways. What is recommended? What are you guys running? What brand and material?