02-14 WRX / 04-21 STI GrimmSpeed Unequal Length Header

GrimmSpeed Unequal Length Header , 2002-2014 Subaru WRX / 2004-2021 STI

The GrimmSpeed Unequal Length Header for the 2002-2014 Subaru WRX and 2004-2021 STI replaces the factory EJ-series exhaust manifold with a high-flow stainless steel unit. While unequal in primary length, the GrimmSpeed design optimizes flow path geometry within that constraint to improve on the OEM manifold’s flow efficiency and thermal performance.

DETAILS

• High-flow design
• 304 stainless steel construction
• Improved flow over OEM manifold
• Ceramic coated options available
• Direct bolt-on
• Fitment: 2002-2014 Subaru WRX / 2004-2021 STI

The factory EJ-series exhaust manifold prioritizes packaging and cost over flow efficiency. GrimmSpeed’s unequal length header uses optimized tube geometry and larger diameter primaries to improve exhaust flow from cylinder head to turbocharger inlet. The improvement in flow reduces turbocharger back pressure and improves spool characteristics.

The stainless steel construction handles the heat cycling that turbo manifolds experience without warping or cracking. The direct bolt-on design uses the factory head and turbocharger connection points , no cutting or welding required for installation.

What’s in the Box

• GrimmSpeed header
• Gaskets
• Hardware

Why Choose GrimmSpeed

GrimmSpeed has been engineering performance parts for Subaru platforms from their Portland, Oregon facility since 2003. Everything they make is designed around real-world use , their engineers drive the same cars their customers drive, which means product decisions are made with genuine platform knowledge behind them. GrimmSpeed designs parts in-house, sources quality materials, and validates fitment on the actual application before release. The result is parts that install correctly the first time, perform as advertised, and hold up under the conditions Subaru owners actually subject their cars to. Whether it is a critical engine component or a cosmetic upgrade, the same attention to detail and fit quality applies across the catalog.

The RallySport Take

The GrimmSpeed unequal length header for the EJ-series Subaru is the header upgrade for builds that want improved exhaust flow on these platforms without the complexity of a full equal-length system. Fits the 2002-2014 WRX and 2004-2021 WRX STI.

Fitment