Let’s be honest—there are a lot of mods out there that look good on Instagram but don’t do much for your Subaru where it counts. If you’re building a WRX, STI, GT, or any turbocharged EJ or FA-powered Subie, here are the top 5 upgrades that actually make a difference to how your car performs, feels, and lasts.
1. Upgraded Silicone Hoses
Why it matters:
Factory coolant, breather, and turbo inlet hoses are prone to softening, cracking, or collapsing—especially under high temps and boost pressure. Swapping to multi-layer silicone hoses (like Fuji Racing’s) gives you better pressure handling, zero heat fatigue, and long-term reliability.
Silicone’s resistance to chemical breakdown and swelling also means fewer leaks, more stable operating temps, and less chance of unexpected dramas at the track—or your next hill run.
Bonus: They tidy up the engine bay and hold their own with OAT coolants, ethanol blends, and high-temp environments.
2. Cylinder Head Studs
Why it matters:
Boost and heat are the enemies of head gaskets. Factory bolts can stretch or lift under sustained load, especially on tuned engines. Upgrading to 14mm head studs from Fuji Racing or ARP increases clamping force and evenly distributes pressure across the head gasket surface.
This upgrade significantly reduces the risk of coolant pressurising, oil leaks, or full-blown gasket failure. Essential for builds over 16psi or any forged bottom-end setups.
3. High-Pressure Radiator Cap & Cooling Upgrades
Why it matters:
The standard Subaru cooling system isn’t built for long stints of abuse. A high-pressure radiator cap raises the boiling point of coolant—meaning your system can hold more heat before losing it through overflow or vaporisation.
Pairing the cap with an aluminium radiator and silicone upper/lower rad hoses helps reduce hotspots, resist heat soak, and maintain stable temps under full send.
Big cooling doesn’t always start with big parts. Sometimes it’s a $40 cap that keeps your motor alive.
4. Thermostatic Oil Sandwich Plate
Why it matters:
Oil that’s too cold or too hot does equal damage. A thermostatic oil sandwich plate ensures oil bypasses the cooler until it hits operating temperature, then directs it through once it’s warm enough. This keeps your oil between the sweet spot of 95–110°C, especially on tuned or track-driven engines.
The Fuji Racing unit offers a true bolt-on solution with AN fittings and sensor ports for future upgrades—slick, smart, and functional.
5. Brake Pads & Rotors
Why it matters:
More power means very little if you can’t rein it in. Upgrading to performance pads and rotors (like DBA T2 Street Series) gives you better bite, shorter stopping distances, and fade resistance—whether you’re in the hills, on track, or dodging kangas at dusk.
If you're after pedal feel and consistency, braided brake lines and a DOT 5.1 fluid flush are a killer combo.
Final Word
These aren’t trendy bolt-ons—they’re the real-world mods that make your Subaru drive harder, stay cooler, stop better, and last longer.
At Roo Racing, we only stock what we’d run ourselves.
No fluff. No filler. Just the non-negotiables.