Description
MAP Mustang GT Stage 3 NA Package — Full Installation and Tune (2018–2023 S550 Facelift)
520–530 bhp from your Coyote V8. No supercharger required.
The S550 facelift Mustang GT is already a formidable car. But between the restrictive factory manifolds, the stock intake, and a tune written for the global market rather than UK 99 RON fuel, there is a significant amount of performance being left on the table. Our Stage 3 NA Package is the definitive naturally aspirated build for the 2018–2023 Mustang GT — transforming a 444–450 bhp stock car into a 520–530 bhp machine that pulls harder, sounds better, and drives with the urgency the Coyote V8 has always been capable of.
Everything is included. Parts, installation, and a bespoke live dyno tune carried out at our workshop in Batley, West Yorkshire. You book a slot, bring the car, and leave with a properly built and properly tuned Mustang.
What’s Included
- Long Tube Headers with High-Flow Cats — your choice of X-Force, American Racing Headers, or Kooks Custom Headers (see header options below)
- JLT Cold Air Intake — replacing the factory airbox with a high-flow cold air system to feed the Coyote properly
- BMR Engine Mounts — solid mounts to eliminate drivetrain movement and improve throttle response and feel
- Full Professional Installation — all components fitted at our workshop by our team
- Bespoke Live Dyno Tune — custom HP Tuners calibration developed live on our in-house Dyno Dynamics rolling road, optimised for 99 RON fuel
The Power Figures
Tuned on 99 RON premium fuel, the Stage 3 NA Package delivers 520–530 bhp on the S550 facelift Mustang GT. This figure is achieved on all three header options — the variation in the package price reflects the different header brands rather than a difference in power output. We always recommend 99 RON to achieve and maintain these figures.
Choosing Your Headers
All three header options are long tube fitment with high-flow catalytic converters, engineered for the RHD S550 Mustang. The differences are in specification, build quality, and lead time:
X-Force Headers — lowest package price, usually in stock. Australian performance exhaust manufacturer with extensive Mustang experience. RHD by design. Strong quality and fitment, excellent value. If you want your build completed quickly without a lead time wait, X-Force is the right choice.
American Racing Headers — mid-range price, built to order. US manufacturer with a long history in Mustang performance. Handcrafted stainless steel construction. Built to order for the RHD S550 application — please allow additional lead time when selecting this option.
Kooks Custom Headers — premium option, built to order. T304 aircraft-quality stainless steel, mandrel-bent primaries, patented scavenging spike collectors, 400-cell Green Cat converters. Kooks is the benchmark for long tube header quality on the Mustang platform and the headers we use on our most demanding builds. Built to order — please allow 6–10 weeks from order for production and delivery. Your workshop installation slot will be confirmed once your headers arrive.
Why Naturally Aspirated
A supercharger is an extraordinary thing — but it is not the right answer for every Mustang. The Stage 3 NA Package builds the engine properly, extracts what the Coyote V8 is genuinely capable of without forced induction, and leaves the car with a linear, progressive power delivery that rewards a driver who knows how to use it. 520–530 bhp through a manual or automatic gearbox, tuned to your specific car on a live rolling road, is a very different experience to a generic off-the-shelf remap — and it is a strong foundation if you decide to add a supercharger further down the line.
How It Works
This product secures your workshop slot and covers the full cost of parts, installation, and tune. Once your order is placed we will contact you to discuss timing, confirm your header choice lead time if applicable, and book your car in. On the day, the full build is carried out at our Batley workshop and your car is tuned live on our in-house Dyno Dynamics rolling road before it leaves.
Vehicle Compatibility
- Model: Ford Mustang GT (S550 Facelift)
- Years: 2018–2023
- Engine: 5.0L Gen 3 Coyote V8
- Drive: Right-Hand Drive
- Transmission: Manual and Automatic compatible
Frequently Asked Questions
What power will my car make after the Stage 3 build?
520–530 bhp on 99 RON premium fuel. This is consistent across all three header options — the price difference between them reflects component cost, not power output. Individual results can vary slightly depending on the condition and specification of your specific car.
What fuel do I need?
99 RON premium fuel is required to achieve the quoted power figures and is what the tune is optimised for. We always recommend 99 RON for all tuned Mustangs. Running 95 RON or E10 will reduce performance and is not recommended on this calibration.
Which headers should I choose?
If you want your build done as quickly as possible, choose X-Force — we usually hold these in stock so there is no significant lead time. If you want the highest specification headers available for the S550 platform and are happy to wait, choose Kooks — they are the benchmark product but require 6–10 weeks build-to-order time. American Racing Headers sit between the two in both price and lead time. Get in touch if you want to discuss which is right for your build.
How long will the build take?
For X-Force headers the full build is typically carried out in one to two days at our workshop. For Kooks or American Racing Headers there is a production lead time before your workshop appointment — we will confirm exact timing once your order is placed and headers are on order.
Is this compatible with the automatic gearbox?
Yes. The Stage 3 NA Package is compatible with both the 6-speed manual and the 10-speed automatic S550 Mustang GT.
What is the difference between the S550 Stage 3 and the S650 Stage 3 packages?
The S550 Stage 3 (this package) is for the 2018–2023 facelift Mustang GT. The S650 Stage 3 is for the 2024+ Dark Horse and Mustang GT. The packages are similar in concept — long tube headers, cold air intake, engine mounts, and a bespoke tune — but the components differ between platforms. Make sure you are selecting the correct package for your model year.
Will these headers fit my RHD Mustang?
Yes. All three header options are specifically sourced and verified for right-hand drive S550 Mustang fitment. Standard US-market headers do not fit RHD cars correctly — every header brand in this package has been selected specifically because it works on the RHD platform.
Can I upgrade to a supercharger later?
Yes. The Stage 3 NA build is a strong foundation for a future supercharger installation. The headers, intake, and engine mounts fitted as part of this package are all supercharger-compatible and will remain in place when you upgrade. Get in touch to discuss our Whipple supercharger packages if you are already thinking about the next step.
Where is the work carried out?
Everything is carried out at our workshop at Smithies Mill, Batley, West Yorkshire, WF17 8NS. The car is tuned live on our in-house Dyno Dynamics rolling road.
What if I already have an intake or other modifications?
Get in touch before ordering and we will assess your current specification and advise on what components you still need. We can adjust the package accordingly.
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