HKS M-Series Super Fire Racing spark plugs are high performance Iridium plugs designed to handle advanced levels of tuning and provide Improved ignition performance, durability, and anti-carbon build-up.

M45IL are for the 3.3t platforms (Stinger, G70) while M45XL are for the 2.0t, 2.5t, and 1.6t platforms. These plugs come pre-gapped to 0.028" from HKS which is suitable for use but we suggest closing the gap down to 0.022" for maximum performance applications.

We are frequently asked which plugs are better for the Kia/Hyandai platform, HKS, or Denso. We've used both brands on our development cars and have found both to be good quality. Generally speaking HKS plugs tend to offer a longer life of 20-35k miles before they need to be replaced, while Denso plugs tend to only last 15-25k miles before needing replacement. For that longer life you do pay a price premium. We've found timing corrections and overall engine performance between them to be otherwise equivalent. 

Beware of counterfeit plugs being sold for $5-10 each on eBay and Amazon. They do not offer the same performance, lifespan, and knock resistance. Spark plugs from palenon performance are guaranteed authentic.

HKS® M-Series Super Fire Spark Plugs Feature

0.6mm Iridium Alloy Center Electrode
Iridium Alloy Center Electrode reduces voltage requirement as well as improves ignition performance and durability.

Outer Electrode with Platinum Chip
The Outer Electrode incorporates a square platinum chip which improves durability, and when combined with the iridium center electrode boosts ignition performance.

Short Type Outer Electrode (Anti-Vibration)
The outer electrode has been shortened and engineered with the ideal shape to decrease weight for resistance against vibration. This anti-vibration design improves the longevity of the outer electrode.

Thermal Edge
After long idling or various combustion conditions, carbon buildup can occur causing misfires. The Thermal Edge of the ceramic insulator will discharge to help decrease carbon deposits.

Spark Support Gap
Discharges will occur in the Spark Support Gap (space between the tip of the insulator and the base of the outer electrode) to help prevent carbon buildup.