HKS High Performance Spark Plugs

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.