Introduction

Upgrading the exhaust system on your BMW M2 Competition is one of the most rewarding modifications you can make. The stock exhaust, while refined, often leaves enthusiasts wanting more volume and a sharper, more aggressive note. A Borla exhaust system is a popular choice among M2 Competition owners for its high-quality construction, weight savings, and distinctive sound profile. This guide provides a complete, step-by-step walkthrough of the installation process, detailed sound test procedures, and performance insights to help you decide if this upgrade is right for your build. Whether you are a seasoned DIYer or a first-time exhaust installer, following these instructions carefully will ensure a clean, leak-free installation and allow you to fully enjoy the enhanced driving experience.

Tools and Materials Needed

Before starting, gather all necessary tools and components. Having everything on hand prevents delays and ensures you can work through the installation without interruptions.

Required Tools

  • Full socket set (metric, 10mm to 19mm, including extensions)
  • Combination wrenches (10mm, 13mm, 15mm, 18mm)
  • Torque wrench (capable of 20-80 ft-lbs)
  • Floor jack and two jack stands (minimum 3-ton capacity)
  • Safety glasses and mechanic’s gloves
  • Penetrating oil (e.g., WD-40 or PB Blaster)
  • Pry bar or exhaust hanger removal tool
  • Rubber mallet (for gentle alignment)
  • Rags and shop towel
  • Flathead screwdriver (for removing hanger bushings)

Components Included in a Typical Borla System

  • Borla cat-back or axle-back exhaust system (depends on model)
  • Stainless steel clamps and bolts
  • New exhaust gaskets (if applicable)
  • Installation instructions from Borla
  • Borla sticker (optional)

Note: Some M2 Competition models require additional exhaust hangers or adapters for a perfect fit. Check your specific Borla part number (e.g., Borla 140719 or 140729) and confirm compatibility with your production year. Consult the Borla website or a trusted retailer before purchasing.

Preparation and Safety

Work in a well-ventilated area—preferably a garage with the door open. The exhaust system can be hot even after the car has cooled, so allow at least one hour of cooldown time after driving. Wear safety glasses to protect against debris and gloves to avoid cuts from sharp metal edges. Ensure the car is on a level surface before lifting.

Lifting the Car

Position the jack under the rear differential or the designated jack point at the rear center of the car. Raise the rear until the wheels are a few inches off the ground, then place jack stands under the factory lift points (the reinforced areas near the rear subframe). Lower the car onto the stands slowly, checking stability. For extra safety, place wheel chocks in front of the front tires.

Important: Never rely solely on a jack. Always use jack stands rated for the vehicle weight.

Step-by-Step Installation

The installation process for a Borla exhaust on the M2 Competition is straightforward but requires patience and attention to detail. The following steps assume you are replacing the entire cat-back section (from the catalytic converter rearward). If you are installing only a rear section (axle-back), some steps may vary slightly.

Step 1: Remove the Stock Exhaust

  1. Spray penetrating oil onto all exhaust clamp bolts, hanger bolts, and the connection at the catalytic converter. Let it soak for 5–10 minutes to loosen rust and corrosion.
  2. Remove the exhaust tips if they are separate from the muffler (stock M2 has bolted tips). Use a 15mm socket to remove the two bolts behind each tip.
  3. Unbolt the muffler section: Locate the two large bolts securing the muffler to the rear subframe. Remove them with a 16mm socket or wrench.
  4. Disconnect the exhaust hangers: There are four rubber hangers supporting the stock system. Using a pry bar or a dedicated hanger removal tool, carefully pry the hanger rods out of the rubber bushings. Apply soapy water if they are stubborn.
  5. Separate the mid-pipe from the catalytic converter: Loosen the two bolts at the flange connecting the mid-pipe to the cat. These are usually 13mm or 15mm bolts. If the joint uses a V-band clamp (uncommon on M2, but possible on some aftermarket setups), loosen the clamp nut entirely.
  6. Lower the stock exhaust: With the help of a second person, slide the entire system out from under the car. If doing it alone, support it with a jack or wooden block while removing the last bolts. The stock exhaust is heavy (approx. 50 lbs), so handle it carefully.

Step 2: Prepare the Borla System

Unbox the Borla exhaust and place it on a clean cloth. Inspect all components for shipping damage. Apply a thin layer of anti-seize compound to all threaded hardware—this makes future removal easier. Do not use regular grease, as it may burn off and create smoke on initial startup.

Note: Borla systems come pre-assembled in most cases. If your system is in multiple sections, loosely assemble them now to ensure proper alignment before tightening.

Step 3: Install the Borla Exhaust

  1. Position the mid-pipe: Slide the middle section (if separate) into place, aligning the flange with the catalytic converter. Use a new gasket if provided; otherwise, reuse the original gasket if it is in good condition. Hand-tighten the bolts.
  2. Attach the muffler section: With the help of an assistant, lift the borla muffler into position. Align the exhaust tips with the bumper cutouts. The tips should be centered and at the same height. This is critical for a professional look.
  3. Install exhaust hangers: Push the hanger rods (on the new exhaust) into the factory rubber bushings. Use a small amount of dish soap as lubricant. Ensure each bushing fully engages.
  4. Secure the subframe bolts: Install and tighten the two bolts that hold the muffler brackets to the subframe. Torque to Borla's specification (usually 35-45 ft-lbs). Do not over-tighten to avoid stripping.
  5. Tighten all clamps and flange bolts: Work from front to back. Torque the mid-pipe flange bolts to 25-30 ft-lbs. For the clamps connecting the mid-pipe to the muffler, tighten gradually, alternating sides. Borla recommends 40-50 ft-lbs for most stainless steel band clamps.
  6. Double-check tip alignment: Loosen the adjustable clamps on the tips (if applicable) and adjust the tips so they are evenly spaced and in line with the bumper. Then tighten those clamps to about 20-30 ft-lbs.

Step 4: Final Checks and Leak Testing

Before lowering the car, perform a thorough inspection:

  • Ensure all clamps and bolts are secure.
  • Verify the exhaust does not contact any underbody components (sway bars, heat shields, driveshaft). Leave at least 1/2 inch clearance.
  • Start the engine (car still on jack stands) and listen for exhaust leaks at every joint. A faint popping or hissing sound indicates a leak. Tighten the affected clamp or flange slightly, then recheck.
  • If no leaks are present, turn off the engine and lower the car.

Pro tip: After lowering, take the car for a short test drive and then recheck all bolts once the system has cooled. Heat cycles can cause clamps to loosen slightly.

Sound Tests: Before and After

Evaluating the sound difference is a crucial part of the experience. Here are three methods to objectively and subjectively compare the new Borla exhaust to the stock system.

Cold Start Test

Record a cold start from the exhaust tail at a distance of 6 feet. The Borla system will produce a noticeably louder, deeper bark on cold start compared to the subdued stock note.
Typical results: Stock idle tone is around 70 dB at idle; Borla can reach 75-78 dB at same distance. On cold start, the Borla may briefly hit 85 dB before settling.

Rev Test (Stationary)

With the car warmed up, perform a series of revs: 2000 RPM, 3000 RPM, 4000 RPM, and 5000 RPM (briefly). Use a decibel meter app or a basic phone recording to capture the sound. Note the increase in volume and shift in tone:

  • Stock exhaust: Muffled, somewhat flat, with minimal rasp.
  • Borla: Sharper, more aggressive, with a distinct "rip" between 3000-4000 RPM. Some models produce a subtle crackle on lift-off (especially the Borla S-Type or ATAK systems).

Wide-Open Throttle (WOT) Drive Test

Take the car on a safe, open road (or a track). Starting in second gear, accelerate from 2500 RPM to redline. The difference is dramatic:

  • Under load, the Borla exhaust produces a deep, metallic roar that intensifies as RPM climbs.
  • Gear shifts are accompanied by a sharp bark—especially on manual transmission models.
  • Coasting down in gear yields a low, gurgling burble that is absent on the stock system.

Note: The sound inside the cabin will increase, but droning is minimal with Borla's patented drone-reducing technology. Most owners report a slight increase in cabin noise at highway cruising (around 2-3 dB) but nothing intrusive.

Performance Benefits and Weight Reduction

While sound is the primary motivator, the Borla exhaust also offers genuine performance improvements on the M2 Competition.

  • Weight savings: The stock exhaust weighs approximately 55 pounds; a Borla cat-back system typically weighs 35-40 pounds, saving 15-20 pounds unsprung weight, which improves suspension responsiveness.
  • Horsepower gain: Depending on the system (cat-back or axle-back), you can expect 5-10 horsepower and 8-12 lb-ft of torque at the wheels. Borla's mandrel-bent tubing reduces backpressure, allowing the engine to breathe more freely.
  • Heat reduction: Borla uses 304 stainless steel, which dissipates heat faster than mild steel, potentially lowering underhood temperatures.

These gains are modest but additive when combined with a tune, intake, or downpipe. For the best all-around improvement, pair the Borla exhaust with a high-flow catted downpipe.

Comparison with Other Options

The M2 Competition has several aftermarket exhaust choices. How does Borla stack up?

  • Borla vs. Akrapovič: Akrapovič is lighter (titanium) and more expensive. Borla offers a deeper note and a more aggressive sound at a lower price point. Akrapovič is more refined; Borla is more raw.
  • Borla vs. Remus: Remus has a sharp, raspy tone. Borla is deeper and less prone to drone. Both offer valved options (Borla does not have active valves for M2, so it's a fixed system).
  • Borla vs. Dinan: Dinan is designed for a more premium OEM+ sound—quieter than Borla. Borla's S-Type system is similar in volume to Dinan's Free Flow, while the ATAK variant is much louder.

For most street-driven M2s, the Borla S-Type (part #140729) provides an ideal balance of volume, tone, and no drone. The ATAK variant is for those who track their car or want maximum aggression.

Maintenance and Longevity

Borla exhausts are built to last, but proper care extends the system's life:

  • Clean the tips regularly: Use a stainless steel cleaner (e.g., Eagle One Never-Dull) to prevent discoloration from carbon buildup.
  • Inspect hangers every oil change: Rubber hangers can dry out; replace them if they crack to prevent exhaust sag.
  • Retighten clamps after 1,000 miles: New gaskets and metal interfaces sometimes settle.
  • Avoid harsh washing chemicals: Borla's polished stainless steel can be ruined by acidic wheel cleaners or brake dust removers.

Borla offers a million-mile warranty on its exhaust systems, covering defects in materials and workmanship. Keep your receipt and register the warranty online within 30 days of purchase.

Conclusion

Installing a Borla exhaust on your BMW M2 Competition is a straightforward weekend project that yields dramatic improvements in sound, weight, and performance. The deep, aggressive tone transforms the character of the car without becoming obnoxious on the highway. With proper installation and a few sound tests, you will appreciate the transformation every time you press the throttle. For those seeking a well-engineered, durable exhaust with a signature sound, Borla remains a top recommendation among BMW enthusiasts.

For additional resources, check out the official Borla product page for your specific model, or browse community sound clips on BimmerPost. If you want a professional installation, many certified shops can complete the job in about 1.5 hours. Whichever path you choose, enjoy the new soundtrack of your M2 Competition.