Spark Plugs Have a (heat range) which needs to be increased as tuning levels increase.

50003-M35iL HKS M-Series Racing Spark Plugs Genesis G35 350Z WRX STI ~~$0.00~~ $34.74	50003-M40HL HKS M-Series Racing Spark Plugs Nissan 370Z GT-R R35 ~~$0.00~~ $38.09	50003-S40IL HKS S-Series Super Fire Spark Plugs Heat Range 8 ~~$0.00~~ $28.29	BCPR7ES NGK Spark Plug Obsolete, Roll Over Part For Replacement Traditional Spark Plug - ~~$2.89~~ $2.50	BKR6ES NGK Traditional Spark Plug ~~$2.89~~ $2.50
BKR7ES-11 NGK Traditional Spark Plug ~~$2.89~~ $2.50	BKR8EIX NGK Iridium IX Spark Plug Heat Range 8 ~~$8.48~~ $7.64	PLFR5A-11 NGK Laser Platinum Spark Plugs Nissan 350z Infiniti G35, Set of 4 ~~$116.24~~ $65.00