HKS 50003-M40I Super Fire Racing Spark Plug #8 - Subaru EJ207/205 / Toyota 1JZ/2JZ / Porsche 996T/997.1 - 1 Piece

HKS 50003-M40I Super Fire Racing Spark Plug #8 – Subaru EJ207/205 / Toyota 1JZ/2JZ / Porsche 996T/997.1

The HKS Super Fire Racing M40I is an iridium‑tipped spark plug developed for high‑performance engines. With a #8 heat range, this medium‑cold plug provides stable ignition both for daily driving and for tuned or modified engines. It delivers reliable spark at high RPM in turbo engines, improving combustion efficiency.

✅ #8 heat range: ideal for tuned and performance engines

✅ Fine iridium electrode for precise ignition

✅ Strong spark even at low voltage

✅ Reduces misfire risk and increases engine stability

✅ Durable construction resists high temperature and pressure

Compared to OEM plugs, the HKS M40I offers longer life and higher performance, delivering safer operation and sharper throttle response in high‑compression or turbo engines.

Compatible Engines and Vehicles

- Subaru Impreza WRX STI EJ207 / EJ205

- Toyota 1JZ‑GTE / 2JZ‑GTE powered Supra, Chaser, Aristo

- Porsche 996 Turbo / 997.1 Turbo

Installation

Dimensions match the OEM plug. Direct replacement. Tighten to the manufacturer’s specs using a torque wrench. Check ECU tuning for compatibility with the heat range.

Note

This plug has a #8 heat range. It may be too cold for very low‑boost or stock engines. Consider your engine type and usage before ordering.