To Cut or Not to Cut? Why Installing Axle-Backs on an S550 Mustang is Tricky
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You want better sound for your 2015–2023 Mustang, but you don't want to spend $1,800 on a full exhaust system.
The solution seems simple: Axle-Back Mufflers.
They cost $500–$800 and replace the quiet factory mufflers with high-flow units from Roush or Borla.
But then you open the box and see the instructions: "Step 1: Cut factory pipe."
Panic sets in. "I thought this was bolt-on?!"
On the S550 Mustang, "Axle-Back" does not mean bolt-on. Ford welded the entire exhaust system as one giant piece. To change the mufflers, you have to physically cut the old ones off.
In this guide, we explain exactly where to cut, which tools you need (a Sawzall is your friend), and why this "scary" install is actually worth it for the sound.
Compare Axle-Back Profiles
Just Noise, or Refined Tone?
|
Brand / Series |
Sound Level |
Tone |
Best For |
|
Roush Axle-Back |
High. |
Hollow / Raspy. |
The "Ford" Sound. Distinctive, aggressive bark. |
|
Borla S-Type |
Medium. |
Deep / Bassy. |
Daily Driving. Zero drone. Perfect cruising volume. |
|
Corsa Sport |
Medium/High. |
Exotic. |
Refinement. Screams at WOT, silent at cruise. |
|
MBRP Installer |
High. |
Raw / Loud. |
Budget. Big sound for a low price. |
|
Ford Performance |
Medium. |
OEM Plus. |
Warranty. Often dealer-friendly. |
Frequently Asked Questions (Axle-Backs)
Do I really have to cut my factory exhaust?
Yes. There is no way around it on the S550 Mustang (2015–2023). Ford welded the entire system from the catalytic converters to the tips as one piece. To install aftermarket mufflers, you must measure and cut the factory pipe (instructions provided) and clamp the new mufflers on.
- Note: If you want a 100% bolt-on solution with no cutting, you must buy a full Cat-Back System.
Will an Axle-Back add horsepower?
Very little (maybe 5 HP). The biggest restriction in the Mustang exhaust is the factory "suitcase" resonator located in the middle of the car. An Axle-Back leaves that resonator in place. It is primarily a Sound Upgrade, not a performance upgrade. To add power, pair it with an X-Pipe or H-Pipe.
Can I install Quad Tips on my 2016 GT?
Yes, but you need a new valance.
The 2015–2017 GT rear bumper valance fits only single tips. To run a 2018+ style Quad Tip Axle-Back (like the Corsa Quad), you must buy a Roush Valance or GT350 Style Valance to accommodate the extra tips.
Change the sound. Save the cash.
Get the rumble you want without replacing the whole system. Shop our verified collection of 2015–2023 Ford Mustang Axle-Backs.