Description
If you’re serious about what your S650 can do, Stage 3 NA Package is where things get properly exciting. This is the most comprehensive naturally aspirated package we offer for the GT and Darkhorse — combining a high-flow cold air intake, full long-tube headers built specifically for right-hand-drive S650s, and a custom MAP tune developed on our in-house dyno. The result? A genuine 530–550 bhp from a car that left the factory making around 450..
This isn’t a parts-in-a-box job. Everything is fitted and tuned by our team at our Leeds workshop, and your car doesn’t leave until it’s running exactly as it should
What’s Included In our Stage 3 NA Package
- JLT Cold Air Intake
- Kooks S650 RHD-Specific Long-Tube Headers with Green Cats
- BMR Engine Mounts
- Full Installation Labour
- Custom Dyno Tune (HP Tuners)
- Dyno Printout
A Note on Lead Times
The Kooks headers in this package are made to order specifically for right-hand-drive S650 Mustangs — they’re not an off-the-shelf part. Please allow 8–10 weeks from order for headers to arrive before we can schedule your fitment. We’ll keep you updated throughout and confirm your workshop slot as soon as they land.
How It Works
Purchasing this package secures your place in our workshop queue. Once your order is placed, our team will be in touch within 24 hours to confirm details, discuss your current setup, and talk through timing. On the day, your car goes straight onto our Dyno Dynamics rolling road — we don’t just bolt parts on and send you home, every Stage 3 build is tuned live to your specific car.
Why Our Stage 3 NA Package?
Stage 1 cleans up the intake. Stage 2 adds cold air. Stage 3 takes on the most restrictive part of the S650’s exhaust path — the factory manifolds. Long-tube headers are the single biggest unlock for naturally aspirated power on the Coyote V8, and paired with our custom tune, the difference is immediately felt on the road. Stronger pull through the mid-range, a more linear power curve, and a sound that does justice to what’s under the bonnet.
Why MAP?
We’ve been developing our S650 Mustang packages since the car launched in the UK. The Kooks headers in this kit are fitment we pioneered for RHD cars — there’s no generic off-the-shelf solution here, and we weren’t prepared to offer one. Every car that leaves our workshop has been signed off on the dyno with a printout to prove it.
Our workshop is based in Batley, West Yorkshire. Customers travel from across the UK for this package — if you’re not local and want to discuss logistics, just give us a call.
Frequently Asked Questions
What power does a stock S650 GT make? Around 444–450 bhp at the wheels on our dyno. Stage 3 typically brings that to 530–550 bhp depending on conditions and the individual car.
Will this affect my car’s warranty? Modifications of this nature can affect manufacturer warranty coverage. We’re happy to talk through this with you before you commit — just get in touch.
Can this be fitted to an automatic S650? Yes. The package is compatible with both manual and automatic S650 GT and Darkhorse variants.
Is there anything I need to do to prepare my car? We’ll go through this with you when we make contact after your order. Generally, we ask that the car is in good mechanical health before arriving — 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.
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