In the Fox Mustang era, Steeda rose to prominence with comprehensive upgrades that elevated pony car performance on the track but retained street civility that allowed for a dual-purpose personality. With each generation of Mustang, the company leveraged its knowledge base to further that improvement. With the release of the 2025 Q850 Street Fighter, the company says it delivered the “most refined, aggressive, and technologically advanced performance package ever offered by Steeda.”

Our engineering team used data from thousands of hours of real-world testing at Sebring and the Nürburgring to fine-tune every component… — Dario Orlando, Steeda

Elevating the output of the Gen 4 Coyote 5.0-liter engine under the hood of the 2025 Q850 is the ubiquitous Whipple Gen 6 3.0-liter supercharger, which boosts engine output beyond 810 horsepower and 640 lb-ft of torque while retaining emissions compliance and a robust warranty. However, this vehicle is engineered for more than brute force.

After an extensive development program at home and abroad, Steeda Performance Vehicles is now offering its top-tier S650, the 2025 Q850 Street Fighter. This 810-horsepower stallion is engineered for optimal performance on and off the track. (Photo Credit: Steeda Performance Vehicles)

“The S650 is an incredible foundation with a stiffer chassis, improved aerodynamics, and cutting-edge technology. We took those strengths and pushed them further—enhancing power delivery with our 810-horsepower Whipple supercharged package, refining suspension geometry to maximize grip, and adding a light-weighting strategy to improve agility,” Bob Adams, President of Steeda Performance Vehicles, said. “On the flip side, we addressed areas where performance could be elevated. Factory suspension components, while good for a broad audience, simply don’t hold up under extreme conditions. Our G-Trac Suspension System eliminates flex, sharpens response, and ensures every bit of power translates into usable performance, making this Mustang a true track weapon.”

Power to the Pavement

By bolstering the chassis rigidity and adding more control to the suspension, Steeda bested a factory S650 Mustang’s lap times around the Sebring International Raceway’s storied track by more than 7 seconds. You can see the full list of upgrades in the sidebar below, but Steeda added more control and adjustment while optimizing the suspension geometry and solidifying the factory independent rear suspension.

“Steeda spent decades refining the Mustang platform, and our experience with the S550 and S650 gave us a significant advantage in developing the Q850 StreetFighter. We didn’t start from scratch — we built upon our deep understanding of the chassis dynamics, suspension geometry, and powertrain capabilities,” Dario Orlando, Founder and President of Steeda, said. “Our engineering team used data from thousands of hours of real-world testing at Sebring and the Nürburgring to fine-tune every component, ensuring that the Q850 delivers a level of performance and control that no other aftermarket Mustang can match.”

Central to the Q850’s performance is a Gen 3 Whipple 3.0-liter supercharger and a companion calibration that boosts the output of its Gen 4 Coyote 5.0-liter engine to 810 horsepower and 640 lb-ft of torque.

While modern cars deliver an amazing balance of performance, comfort, and safety, they pay a penalty in increased weight. More power can overcome some of the weight penalty, but the benefits of shedding excess poundage are exponential, so Steeda focused Q850 on optional upgrades that make up a comprehensive Optimum Performance Weight Savings Package.

Shedding Pounds For Performance

“Weight is the enemy of performance — plain and simple. Shedding excess pounds improves every aspect of the Q850’s dynamics: acceleration, braking, cornering, and even tire longevity,” Dario explained. “Our Steeda Optimum Performance Weight Savings Package allows owners to dial in the level of weight reduction they want, giving them a more nimble, balanced, and predictable driving experience. By removing up to 178 pounds, we’ve created a Mustang that responds quicker, brakes harder, and carries more speed through corners — without sacrificing comfort or daily drivability.”

There is no one magic bullet when it comes to shedding weight on a modern performance machine, however. Instead, Steeda shaved off the pounds incrementally via its standard and optional upgrades. The hardware that contributed to the Q850’s diet is extensive, including Steeda ProAction front coilovers and rear shocks (10 pounds), aluminum or carbon fiber one-piece driveshaft (16 pounds), Steeda Trident Wheels (24 pounds), Lithium-Ion Battery (35 pounds), Steeda Road Race Front K-Member (28 pounds), Rear Seat Delete Kit (34 pounds) Steeda Cat-Back Performance Exhaust System (8 pounds), Steeda Resonator Delete Kit (8 pounds), and Steeda Two-Piece Brake Rotors (15 pounds).

The result of these options is said to deliver a neutral feel behind the wheel and a performance edge in every on-track performance metric.

“The Steeda Q850 StreetFighter isn’t just about horsepower — it’s about total vehicle performance. It’s the only Mustang developed with both Sebring and Nürburgring testing, ensuring real-world capability on the most demanding circuits,” Bob added. “It features an industry-leading suspension system that provides unmatched handling precision, a supercharged powertrain delivering relentless acceleration, and a weight-saving strategy that enhances agility. Plus, it’s backed by a three-year/36,000-mile warranty, proving that extreme performance and reliability can coexist. This isn’t just a Mustang — it’s the ultimate Mustang.”

Steeda developed and tested its Q850 package at Sebring International Raceway and on the Nürburgring Nordschleife to ensure it delivered on-track performance without a penalty on the street.

If the 2025 Steeda Q850 Street Fighter sounds like your dream S650, it will add $36,995 on top of the price of your base Mustang. You can spec one out by visiting the Steeda Performance Vehicles website right here.