I want to change my spark plugs and coils but i don't know what km to change them.

 

there's no right or wrong on this... depends on what condition they're in. For the coils it's looking to be at roughly 80k/4 years that most people start to show some suckage.. for the plugs... that all depends.. just ask Al

 

About the spark plugs, RevRx8 it depends on how often you drive. If you drive a lot then check them around 25k miles.
I drive a lot so I do my spark plugs and coils at the same time about less than a year.

 

im using rx7 plugs

 

I've done my coils at 50 and 90, both times showed signs on arcing through the bottom of the coils, did my plugs at the same time too, wires at 90

 

Just did my plugs at 56k might take my coils off to check their condition soon, but just looking at the bottom of them is still no true indication of their condition.