This Borla cat-back exhaust system is built for the verified 2004-2009 Mazda 3 S application listed below. Select it by exact manufacturer part number 140121 and confirm the full engine, drivetrain, body, wheelbase, factory-exhaust, and Borla application notes before ordering.

Key Features

• T-304 Stainless Steel Construction: Aerospace-grade material resists corrosion for long-lasting durability and includes polished 4-inch single left rear exit tip.
• 2.5-Inch Tubing Diameter: All-welded mandrel-bent pipes ensure smooth exhaust flow for better throttle response and efficiency.
• Bolt-On Installation: Direct fit with no cutting or welding required, compatible with stock cat-back hangers.
• Straight-Through Muffler Design: Provides distinctive Borla exhaust note while delivering measurable power and torque increases on dyno tests.
• Bolt-on system installs in 30-60 minutes with basic hand tools; no drone at highway speeds.
• Over 40 years pioneering stainless steel exhaust for street and racing.

Fitment

Specifications

What’s Included

One new Borla product identified by manufacturer part number 140121. Clamps, hangers, gaskets, tips, pipes, tools, and companion parts are included only when expressly listed for this exact part number.

About Borla

Borla develops stainless-steel exhaust systems, mufflers, tips, pipes, and related components for vehicle-specific and universal performance applications. Product selection remains exact-application and exact-part-number specific.

Related Borla Products

• Borla 00-06 Toyota Tundra 4.7L V8 AT/MT 2WD/4WD Truck Side Exit Catback Exhaust
• Borla 02-07 WRX Twin Tip Hush Catback Exhaust
• Borla 03 Thunderbird 3.9L V8 AT RWD 2 DR Catback Exhaust

Browse the Borla collection for related exhaust systems and components.

Frequently Asked Questions

Will this Borla part fit my 2004-2009 Mazda 3 S?
That application is listed, but confirm the engine, drivetrain, body or cab style, wheelbase, factory exhaust layout, tip opening, and every Borla application note before ordering.

Will this change require an engine tune?
A cat-back, axle-back, tip, muffler, or post-catalyst component usually does not require tuning, but confirm the exact application, emissions configuration, oxygen-sensor locations, and local requirements before installation.

What should I inspect before installation?
Check the shipping carton and components against the exact part number, then inspect clamps, hangers, gaskets, mating flanges, clearances, tip alignment, and required reused factory hardware before removing the original exhaust.

Installation Instructions

Follow the current Borla instructions and vehicle service information for this exact part number. Let the exhaust cool, support the vehicle safely, compare all parts before removal, protect sensors and wiring, use the specified clamps and torque values, align all joints and tips without preload, confirm body and suspension clearance, check for leaks, and retorque after the first heat cycles. Professional installation is recommended.