I am getting my car serviced next week but i'm unsure on which spark plugs to get.

Car is an STI5 Type R and the plugs i was getting are the HKS Iriduim ones, the only thing i'm not sure about is the heat range to get.

They are recommending me the 7s but wondering whether to get the 8s.
Will a get any running probs by running 8s instead of 7s.
I haven't done that many mods to the car yet but plan to do so in the near future.
Present mods consists of full de-cat and panel filter.


Mel.

Sorry just noticed that i've posted this in the wrong section.
Mods could you please move to general technical.


Thanks


Mel.