For a 2013 to 2018 Ford Focus ST, the Borla S-Type is the mildest and most refined catback, the COBB 3 inch stainless system is the drone-free choice built to pair with an Accessport tune, the Injen is the premium titanium-tip option, and the AWE Track Edition is the loudest and the least expensive. All four are direct-fit stainless steel systems that run from about $783 to about $1,282, so the choice comes down to sound, tubing, and budget.
The factory Focus ST exhaust is one of the first things owners want to change, mostly because it sounds too tame for a car with a turbo four-cylinder and a sporting reputation. A catback replaces everything behind the catalytic converter, so it changes sound and flow without touching the emissions hardware up front. This guide compares four systems that Wrench Masters carries, explains the real differences between them, and helps match each one to the kind of owner who will enjoy it most.
What a Catback Actually Changes
A catback swaps the factory pipes, resonator, and muffler for a freer-flowing stainless system. The main effects are a louder and more aggressive exhaust note and a small reduction in backpressure. It does not touch the catalytic converter or the downpipe, which is where the bigger flow gains live on a turbocharged car.
That distinction matters for expectations. A catback is mostly about sound and looks, with a modest flow benefit, and the broader explanation in downpipe versus catback versus turboback applies to the Focus ST too, even though it was written for the WRX. Owners chasing real power gains should treat the exhaust as one part of a larger plan.
Check Fitment First
All four systems fit the 2013 to 2018 Focus ST with the 2.0 liter turbo engine, the only version sold in the US. Some listings elsewhere extend the range by a year, but the Focus ST ended in 2018, so every system here covers the full production run. Owners of the 2015 model should note that Ford designed it with four exhaust hangers but only fitted three on the factory system, which COBB addresses in its kit.
Borla S-Type: The Mildest and Most Refined
The Borla S-Type is built from T-304 stainless steel with a 2.5 inch main pipe that splits into dual 2 inch tailpipes, ending in polished 4.5 inch rolled angle-cut tips. Borla describes the sound as the classic S-Type note with no drone inside the cabin, and one dealer lists the system sound as mild and close to stock, only slightly louder at cruise with a more aggressive note under acceleration.
Borla backs the system with a Million-Mile Warranty, while AWE offers a lifetime warranty on its system as well. At about $1,088 it sits in the upper middle of the price range, and the narrower 2.5 inch tubing is the main technical difference from the other three systems, which all use 3 inch piping. Owners who want a noticeable upgrade without a loud car around town will find this the safest fit.
COBB 3 Inch Stainless Catback: Drone-Free and Tune-Friendly
The COBB catback uses full 304 stainless steel with 3 inch CNC mandrel-bent tubing, custom inline mufflers, and dual 4 inch double-wall slash-cut tips. COBB describes the exhaust note as unique and drone-free, and the system is part of its Stage 3 package. The company also states that it is not an emissions-related part and can be used on emissions controlled vehicles.
The best reason to choose it is the tune. COBB says the system is tuned out of the box with the Accessport, which makes it a matched part of its Stage 3 setup. Owners already running or planning an Accessport can read the COBB AccessPORT V3 listing and the Stage 1 Plus Power Package to see how the exhaust fits into COBB’s staged path. COBB’s install notes add one practical warning, since the factory exhaust is a one-piece design that has to be cut out, which means a cutting tool is part of the job.
Injen 3 Inch Catback: Titanium Tips and Dual Resonators
The Injen system uses 76 mm, which is 3 inch, T304 stainless steel tubing that is mandrel bent and TIG welded in Pomona, California. It adds dual Injen resonators to clean up unwanted frequencies, and dual 4.5 inch burnt titanium tips. Injen describes the note as aggressive and crisp, and the flange design is meant to speed up installation.
It is the most expensive system here at about $1,282, and much of that price goes toward the titanium finish and the handcrafted construction. Injen recommends that a qualified technician perform the installation. Owners who care about appearance as much as sound, and who want resonators to keep the note clean, are the natural buyers.
AWE Track Edition: The Loudest and Least Expensive
The AWE Track Edition uses 3 inch T304L stainless steel in a straight-through, non-baffled design with 4 inch double-wall slash-cut chrome silver tips. It is the Touring Edition minus AWE’s 180 Technology resonator, the part designed to cancel drone. AWE calls it the rowdiest of its Focus ST systems and warns that it gets loud in the midrange, which is why AWE does not accept returns on this version.
At about $783 it is the least expensive system here, and AWE backs it with a lifetime exhaust warranty. AWE states maximum gains of 7 horsepower and 12 lb-ft of torque at the crank and guarantees no check engine light. Those figures are AWE’s own claims, and they illustrate the point that a catback is mostly about sound. AWE also sells a quieter Touring Edition for owners who find this one too loud, though that version is not part of this comparison.
Which Exhaust Fits Which Owner
A daily driver who wants the mildest upgrade fits the Borla. An owner building around an Accessport tune fits the COBB. A buyer who cares about titanium tips and a resonated note fits the Injen, and a driver who wants maximum volume at the lowest price fits the AWE. Sound is subjective, so owners who are unsure should talk to people who have driven each system, since the AWE cannot be returned once opened.
Installation is the other deciding factor. The Wrench Masters shop in St. Petersburg installs performance parts, and appointments can be scheduled online. More options live in the catback category and the wider exhaust category.
Where an Exhaust Fits in a Bigger Build
An exhaust works best as one piece of a plan. The Ford Focus ST stimulus package guide pairs a catback with an intake and a blow off valve, and the Turbosmart plumb-back versus dual-port comparison covers the blow off valve side. Handling upgrades belong in the same plan, and the must have suspension upgrades guide and the Whiteline sway bar links guide cover that side.
Owners planning more power should look at the downpipes category, since the downpipe changes flow far more than a catback does. More guides for the car live in the Ford blog category.
Frequently Asked Questions
What is the best catback exhaust for a Ford Focus ST?
It depends on the sound wanted. The Borla S-Type is the mildest, the COBB is drone-free and tune-friendly, the Injen adds titanium tips and resonators, and the AWE Track Edition is the loudest and cheapest.
Will a catback exhaust add horsepower to my Focus ST?
Only a little. A catback mainly changes sound and slightly reduces backpressure. AWE claims maximum gains of 7 horsepower and 12 lb-ft at the crank, and a downpipe changes flow far more.
Which Focus ST exhaust is the quietest?
The Borla S-Type is the mildest of the four. Borla describes its sound as having no drone inside the cabin, and one dealer lists it as mild and close to stock.
Is the AWE Track Edition too loud for daily driving?
It can be. AWE says the Track Edition gets rowdy in the midrange and may be too much for many owners, which is why AWE does not accept returns on it. A quieter Touring Edition is available for those owners.
Do I need a tune after installing a catback exhaust?
No tune is required for an exhaust. COBB states that its catback is tuned out of the box with the Accessport, which makes it a good match for owners already running one.
Can I install a Focus ST catback exhaust myself?
It is possible, but plan for effort. COBB notes that the factory exhaust is a one-piece design that has to be cut out, and Injen recommends professional installation. A shop appointment avoids the guesswork.
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