Invidia 3" Downpipe to 2.5" Exhaust Adapter – 2008+ Subaru WRX / STi (GR/GV) | Connects 3" Aftermarket Downpipe to 2.5" Cat-Back Exhaust System

The Invidia 3" Downpipe to 2.5" Exhaust Adapter for the 2008+ Subaru WRX and STi (GR/GV chassis) is a direct-fit exhaust adapter that allows a 3" aftermarket downpipe to connect to a 2.5" cat-back exhaust system — solving one of the most common exhaust fitment challenges on the GR/GV WRX and STi platform. Many aftermarket downpipes for the GR/GV WRX and STi are 3" diameter for maximum flow, while many popular cat-back exhaust systems use a 2.5" inlet — creating a diameter mismatch that requires an adapter for correct connection. Invidia's adapter provides a clean, leak-free transition between the 3" downpipe outlet and the 2.5" cat-back inlet. Invidia is one of the most respected exhaust brands for Subaru applications in the North American market — known for their quality stainless steel exhaust systems, downpipes, and exhaust accessories for the WRX and STi platforms.

Key Features:

• 3" to 2.5" diameter transition — adapts a 3" downpipe outlet to a 2.5" cat-back exhaust inlet — the correct solution for GR/GV WRX and STi builds running a 3" downpipe with a 2.5" cat-back
• Direct-fit for 2008+ GR/GV WRX/STi — engineered for the 2008+ Subaru WRX and STi GR/GV chassis exhaust system — correct connection geometry for the GR/GV downpipe and cat-back connection point
• Invidia quality — manufactured by Invidia, one of the most respected exhaust brands for Subaru applications in the North American market
• Clean transition — provides a clean, leak-free diameter transition between the 3" downpipe and 2.5" cat-back — no exhaust leaks at the connection point

Why This Adapter Is Needed:

The 2008+ Subaru WRX and STi (GR/GV chassis) is one of the most popular platforms for exhaust system upgrades in the North American performance market. Many GR/GV owners upgrade to a 3" aftermarket downpipe (catted or catless) for improved turbocharger spool and exhaust flow — but many popular cat-back exhaust systems for the GR/GV use a 2.5" inlet diameter. Without an adapter, the 3" downpipe outlet cannot connect cleanly to the 2.5" cat-back inlet — resulting in exhaust leaks, noise, and reduced system performance. Invidia's 3" to 2.5" adapter provides the correct diameter transition for a clean, leak-free connection between a 3" downpipe and a 2.5" cat-back on the GR/GV WRX and STi.

Common Application Scenarios:

• 3" aftermarket downpipe + 2.5" cat-back: The most common use case — a GR/GV WRX or STi running a 3" aftermarket downpipe (Invidia, Perrin, Grimmspeed, or other brands) with a 2.5" cat-back exhaust system that does not include a 3" inlet option
• Exhaust system mixing: Mixing downpipe and cat-back brands where the downpipe outlet and cat-back inlet diameters do not match — the Invidia adapter provides the correct transition

Specifications:

• Brand: Invidia
• Part Number: INVHS02SWIAPD
• Barcode: HS02SWIAPD
• Inlet Diameter: 3"
• Outlet Diameter: 2.5"
• Application: 2008+ Subaru WRX / WRX STi — GR (hatchback) / GV (sedan) chassis
• Weight: 1.3 lbs

Fitment Information:

• 2008–2014 Subaru WRX — GR hatchback / GV sedan — EJ255
• 2008–2014 Subaru WRX STi — GR hatchback / GV sedan — EJ257
• For use with 3" downpipe outlet connecting to 2.5" cat-back inlet
• Note: Verify your specific downpipe outlet diameter and cat-back inlet diameter before ordering — confirm that a 3" to 2.5" adapter is the correct solution for your specific exhaust combination. Verify correct connection method (slip-fit, clamp, or flange) for your specific downpipe and cat-back combination.

What's Included:

• Invidia 3" to 2.5" exhaust adapter — 2008+ Subaru WRX/STi GR/GV (INVHS02SWIAPD)
• Refer to Invidia's product documentation for complete kit contents and hardware

Installation Notes:

• Allow the exhaust system to fully cool before installation — never work on a hot exhaust system
• Apply anti-seize compound to all exhaust fasteners — exhaust fasteners are subject to extreme heat cycling and will seize without anti-seize
• Verify correct adapter orientation before installation — the 3" end connects to the downpipe outlet and the 2.5" end connects to the cat-back inlet
• Use a quality exhaust clamp to secure the adapter connections — verify correct clamp size for both the 3" and 2.5" connections
• Check for exhaust leaks after installation — start the engine and inspect all connection points for leaks before driving

Why Invidia?

Invidia is one of the most respected exhaust brands for Subaru applications in the North American market — known for their quality stainless steel exhaust systems, downpipes, and exhaust accessories for the WRX and STi platforms. Invidia's exhaust accessories are engineered for the specific fitment requirements of the GR/GV WRX and STi — correct dimensions, correct connection geometry, and correct material quality for a reliable, leak-free exhaust system. For GR/GV WRX and STi owners who need a quality 3" to 2.5" exhaust adapter from a trusted Subaru exhaust brand, INVHS02SWIAPD is the correct choice.

Perfect For:

• 2008+ Subaru WRX and STi (GR/GV) owners running a 3" aftermarket downpipe with a 2.5" cat-back exhaust system who need a clean, leak-free diameter transition adapter
• GR/GV exhaust system builds where the downpipe and cat-back brands use different outlet/inlet diameters and a quality adapter is required for a correct, leak-free connection
• WRX and STi owners who want a quality Invidia exhaust adapter engineered specifically for the GR/GV platform's exhaust system connection geometry

Note: Verify 3" downpipe outlet and 2.5" cat-back inlet diameters before ordering. Verify correct connection method for your specific exhaust combination. Apply anti-seize to all fasteners. Check for exhaust leaks after installation. Allow exhaust to cool fully before installation.