Mick’s Subaru Forester STI came into the workshop ready for a worthwhile performance upgrade: a new Grimmspeed top-mount intercooler and matching tray.

The factory intercooler performs well in standard form, but increased boost, spirited driving and further engine modifications can quickly expose its limitations. Upgrading the intercooler helps improve charge-air cooling, reduce heat soak and provide more consistent performance.

Removing the Factory Intercooler

The installation began with the removal of the original top-mount intercooler, along with the factory intercooler tray and associated ducting. Everything was carefully inspected before fitting the new components, including the turbo outlet hose, throttle-body connection and mounting points.

This is also a good opportunity to check for worn hoses, damaged clamps or signs of boost leaks.

Fitting the Grimmspeed Intercooler and Tray

The Grimmspeed top-mount intercooler offers a larger and more efficient core than the standard unit. Its increased capacity allows it to handle higher airflow while helping keep intake temperatures under control.

The new Grimmspeed tray was then installed to provide the correct support and alignment. Once the intercooler was positioned, the hoses were connected and all clamps were tightened evenly to ensure a reliable seal.

Care was taken to check clearance around the bonnet, scoop and surrounding engine-bay components. Correct alignment is essential—not only for a clean installation, but also to avoid unnecessary stress on the pipework and intercooler mounts.

Final Checks

After installation, the system was checked for:

- Secure intercooler mounting

- Correct hose alignment

- Tight clamps and fittings

- Adequate bonnet and scoop clearance

- Potential boost leaks

The Forester STI was then started and inspected for any signs of leaks or contact. With the new intercooler fitted, the engine bay looks sharper and the car is better prepared for consistent performance under load.

Ready for the Next Stage

The Grimmspeed top-mount intercooler and tray are a great upgrade for Mick’s Forester STI, especially as part of a wider performance setup. While an intercooler alone does not guarantee a specific power increase, it can provide improved temperature control and more repeatable performance.

With the installation complete, Mick’s Forester STI is ready for plenty more boost, street driving and track-day fun .