IAG Equal Length 3-Bolt Header & Uppipe 02-14 WRX / 04-21 STI / 05-09 Legacy GT / 04-08 Forester XT | 304 Stainless Steel | Performance Exhaust Header & Uppipe

Overview

The IAG Equal Length 3-Bolt Header & Uppipe is a precision-engineered exhaust upgrade designed specifically for Subaru WRX, WRX STI, Legacy GT, and Forester XT models spanning 2002 to 2021. This high-performance header system replaces the restrictive factory manifold with a 4-2-1 equal-length design that optimizes exhaust flow and turbo spool characteristics. Paired with a 3-bolt stainless steel uppipe, this kit ensures a leak-free, durable connection to your turbocharger, making it an ideal choice for enthusiasts seeking improved power delivery and throttle response.

Crafted from premium 304 stainless steel, the IAG header features fully TIG-welded construction and cast stainless flanges for exceptional strength and longevity under extreme heat cycling. The 45mm pipe diameter and slip-joint expansion section accommodate thermal expansion while maintaining structural integrity. IAG’s engineering focus on equal-length tubing and a merged collector design reduces turbo lag by approximately 300 RPM, delivering smoother and more consistent power across the entire RPM range.

Subaru owners will appreciate the tangible performance gains and refined exhaust tone this header system provides. The equal-length design shifts the exhaust note away from the traditional boxer rumble to a smoother, more aggressive sound that complements the sporty character of these platforms. Whether you’re building a street performance car or a track-focused machine, this header and uppipe combination is a foundational upgrade that supports further tuning and modifications.

Features & Specifications

This IAG Performance Equal Length Header & Uppipe is engineered for Subaru WRX, WRX STI, Legacy GT, and Forester XT models and features a 45mm pipe diameter with a 4-2-1 equal-length design. Constructed from 304 stainless steel with cast stainless flanges and TIG welding, it delivers improved turbo spool and exhaust flow for Subaru enthusiasts seeking enhanced power and reliability.

• Brand: IAG Performance
• Product: Equal Length 3-Bolt Header & Uppipe
• Part Number: IAG-EXT-1001
• Fitment: 2002-2014 WRX, 2004-2021 STI, 2005-2009 Legacy GT, 2004-2008 Forester XT
• Material: 304 Stainless Steel
• Finish: Natural Stainless Steel
• Construction: Fully TIG Welded with Cast Stainless Flanges
• Origin: Not Specified
• Pipe Diameter: 45mm
• Design: 4-2-1 Equal Length Header with Merged Collector
• Uppipe Connection: 3-Bolt Cast Flange with Multi-Layer Gasket
• Expansion Joint: Slip-Joint for Heat Cycling Flex
• Power Gains: Turbo spool improved by approximately 300 RPM
• Tuning Required: Recommended for optimal performance

Key Benefits

• Performance: Improves turbo spool by 300 RPM, enhancing throttle response and mid-range power delivery.
• Durability: 304 stainless steel construction with TIG welding and cast flanges ensures long-lasting strength under heat stress.
• Fitment: Designed specifically for multiple Subaru platforms with a 3-bolt flange for a secure, leak-free connection.
• Exhaust Flow: Equal length 4-2-1 design optimizes scavenging and reduces backpressure across the RPM range.
• Sound Quality: Alters exhaust tone from boxer rumble to a smoother, more refined note without sacrificing character.
• Installation: Includes all necessary hardware and multi-layer gaskets for a complete upgrade.

What's Included

• 1× IAG Equal Length Stainless Steel Header
• 1× IAG 3-Bolt Stainless Steel Uppipe
• 1× 3-Bolt Uppipe Gasket
• 3× Uppipe to Manifold Zinc Plated Bolts and Nuts
• 5× Uppipe to Turbo Threaded Studs
• 1× EGT Plug
• 6× Copper Flange Nuts (Manifold to Head)
• 2× Manifold to Cylinder Head Gaskets
• 1× Uppipe to Turbo Gasket

Installation & Compatibility

Installation of the IAG Equal Length Header & Uppipe requires moderate mechanical skill and basic hand tools. While the kit includes all necessary hardware and gaskets, professional installation is recommended to ensure proper torque settings and leak-free sealing, especially given the critical nature of exhaust flange connections. The slip-joint expansion section accommodates thermal expansion, reducing stress on the exhaust system during heat cycles. Tuning is recommended after installation to optimize air/fuel ratios and maximize power gains.

• Professional Installation: Recommended
• Modifications Required: None; direct bolt-on fitment
• Verify Compatibility: Confirm fitment for your specific year and trim level within the supported range

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