Stage 3 NA Package for S650 Mustang GT & Dark Horse

Description

If you’re serious about what your S650 can do, the Stage 3 NA Package is where things get properly exciting. It’s the most complete naturally aspirated package we offer for the Mustang GT and Dark Horse. It combines a JLT cold air intake, RHD-specific long-tube headers with high-flow cats, BMR engine mounts, and a custom tune developed on our in-house dyno. The target is 530–550 bhp from a car that leaves the factory at around 440–450 bhp.

Choose between two header options: Kooks or Manta. Both are built for right-hand-drive S650s, so they fit UK cars properly. The difference is in construction, cats, lead time and price, explained below.

This isn’t a parts-in-a-box job. Our team fits and tunes everything at our West Yorkshire workshop, and your car doesn’t leave until it’s running exactly as it should.

What’s Included

• Kooks RHD long-tube headers with 400-cell Green Cats or Manta RHD long-tube headers with 400-cell high-flow cats
• JLT cold air intake
• BMR engine mounts
• Full installation labour
• Custom live dyno tune using HP Tuners
• Dyno printout

Kooks or Manta: Which Headers?

Choose Kooks if you want the premium option: hand-built, with Kooks’ scavenging collectors and Green Cats rated to 750 WHP. If there’s any chance you’ll supercharge your S650 later, Kooks is the one to choose. The headers and cats can stay on the car when you add boost, so you only buy once. It’s worth the wait if you’re not in a rush.

Choose Manta if you’re staying naturally aspirated and want to get booked in sooner for less. You still get proper RHD fitment, cats rated to 500 WHP (plenty for Stage 3), and the same tune and installation.

Lead Times

Kooks: the headers are built to order specifically for right-hand-drive S650, so please allow 6–10 weeks for them to arrive before we schedule your fitment. We’ll keep you updated and confirm your workshop slot as soon as they land.

Manta: usually in stock, so we can book you in as soon as a workshop slot opens.

How It Works

Buying this package secures your place in our workshop queue. Our team will be in touch within 24 hours to confirm details, discuss your current setup and agree on timing. On the day, your car goes onto our Dyno Dynamics rolling road. We don’t just bolt parts on and send you home: we tune every Stage 3 build live to your specific car, and you leave with a dyno printout.

Watch the Build

See an S650 go from stock to 550 bhp naturally aspirated on our dyno:

Why Stage 3?

The factory exhaust manifolds are the most restrictive part of the S650’s exhaust path. Long-tube headers are the single biggest naturally aspirated power gain on the Coyote 5.0 V8. With the cold air intake and our custom tune, you get stronger mid-range pull, a more linear power curve, and a sound that matches what’s under the bonnet.

Not ready for headers yet? Our Stage 1 ECU tune works on stock hardware. You can upgrade to Stage 3 later.

Why MAP?

We’ve been developing S650 Mustang packages since the car launched in the UK, and we worked with Kooks to develop their RHD S650 header fitment. Every car that leaves our workshop has been signed off on the dyno, with a printout to prove it.

Our workshop is in Birstall, West Yorkshire, just off the M62 near Leeds. Customers travel from across the UK for this package. If you’re not local and want to discuss logistics, just give us a call.

See more upgrades for the S650 Mustang GT and Mustang Dark Horse.

Frequently Asked Questions

How much power does a stock S650 make?

Ford rates the UK-spec Mustang GT at around 440 bhp and the Dark Horse at around 450 bhp. Stage 3 typically takes either car to 530–550 bhp, depending on conditions and the individual car.

Is the Dark Horse different to the GT?

Both cars use the 5.0 Coyote V8 and the same headers. The Dark Horse starts with slightly more power. We tune every car individually on our dyno, so the tune suits your specific car.

What’s the difference between the Kooks and Manta packages?

Both are RHD-specific long-tube headers with 400-cell high-flow cats and come with the same intake, mounts, installation and tune. Kooks are hand-built in the USA to order, with scavenging collectors and Green Cats rated to 750 WHP. Manta are made in Australia, have cats rated to 500 WHP and are usually in stock, so you can be booked in sooner for less.

I’m planning to supercharge later. Which headers should I choose?

Choose Kooks. Their Green Cats are rated to 750 WHP, which covers a typical supercharged S650. The Manta cats are rated to 500 WHP, which is ideal for Stage 3 but not enough for boost. Tell us your plans when you order, and we’ll make sure the setup suits where you want to end up.

Will this affect my car’s warranty?

Modifications of this kind can affect manufacturer warranty cover. We’re happy to talk this through with you before you commit, so just get in touch.

Do I need to tell my insurer?

Yes. Always declare performance modifications to your insurer.

Can this be fitted to an automatic S650?

Yes. The package suits both manual and automatic S650 GT and Dark Horse models.

How long will my car be with you?

Most Stage 3 NA builds are completed within 3 working days, including the dyno tune.

Is there anything I need to do to prepare my car?

We’ll go through this with you after your order. In general, we ask that the car be in good mechanical health before it arrives. If there are any known issues, let us know in advance.

What if my car needs additional work during the build?

If we find anything unexpected during the install, we’ll contact you before proceeding. No surprises.