My 2006 evo has about 50k miles. How do my plugs look? Am I overdue on replacing them or can I continue using them? How do you know when your plugs have reached the end of its life?

TIA

 

Change them, they aren't very expensive get bpr7es if you have bolt-ons. They are cheap and good. Change your spark plugs more often than every 50k miles. What mods do you have? Have you had the car since it was new?

 

Stock NGK plugs for an evo 9 are ILFR7H

Keep in mind that spark plugs are not cross-compatible with 8's and 9's

 

I've had the car since new in 2006. The car has HKS GTII turbo and all other bolt-ons and cams. I am making 390whp/350wtq on a dynojet. Should i go 1 step colder?

 

stock is fine still

 

its not necessary but i change my every oil change. its cheap and only takes like five minutes.

 

evo 8 are cheap. evo 9 are not cheap if you run factory plugs. 3x the price of 8's almost