GT4 Series Conversions for S550 Mustang


"If your car doesn’t turn you on when you turn it on, it’s not a Kenny Brown Mustang.”

Kenny Brown Performance GT4 Mustang - Meet Marilyn

Driving a KENNY BROWN GT4 Series Mustang gives you the uncanny combination of pure exhilaration and calm.

Exhilaration because KENNY BROWN cars are pure visceral Vroom!

Calm because at the same time delivering a feeling of total control and supreme confidence.

It’s as if you melt into the seat, hands meld with the steering wheel, and your right foot plays a concerto in get-it-on sharp. You become one with the car and the car becomes one with the road.

So whether your looking for a Spirited Touring, Performance Street, Track Day or Full Competition car - nothing comes close to the Pure Performance you'll get from a KENNY BROWN Mustang.

Marilyn Mustang GT4 Heritage Series Kenny Brown Cars

It’s easy to order your bespoke KENNY BROWN Mustang:

1. Choose your level of performance from one of the GT4 performance packages.

2. Work with Kenny one-on-one to choose the right package and options specific for your driving style, intended use and budget.

3.  Kenny will then custom-tailor your Mustang specifically for your driving desires. 

4.  Then turn the key, hit the gas and strap on a smile! Kenny Brow Mustangs give you super high SPM – Smiles Per Mile.

5  Now you have a custom Best-in-Class high-performance Mustang built just for you by the Master himself.

All Kenny Brown Mustang conversions are custom contented to your specific needs, desires and driving ambitions. Kenny works with you one-on-one to help develop the package that’s right for you and your budget.

Which KENNY BROWN GT4 Series Mustang Hits YOUR Performance SWEET SPOT? 

Marilyn Mustang GT4 Kenny Brown Cars Heritage Series


A Kenny Brown's GT4/CS-R (Club Sport Racer) Mustang that is outrageously fast, exhilarating to drive and pretty much dominates at track days. The GT/CS-R is the top-of-the-range of the Kenny Brown naturally aspirated line of GT4 Series Mustangs and the best premium late-model track car Kenny offers.

Why the name "Marilyn" you may ask? As a tradition, we (as well as our customers) have a penchant to name our special custom-built cars rather than reference them as just a number. Often the name has a tendency to encompass the personality of the particular car as well.

Marilyn is named after Marilyn Monroe and has rightfully earned her name. She's a really fast, drop-dead gorgeous platinum blonde that everybody wants to get their hands on, but no one can catch.

Aside from being incredibly fast, extremely well-balanced with precision handling and totally amazing to drive. It’s hard to find the words to describe the exhilaration you get when driving Marilyn (or any other Kenny Brown GT4/CS-R Mustang for that matter) other than she’ll take your breath away - in a very, very good way. So the name Marilyn fits!

So, What Will You Name Your Kenny Brown Mustang?

Marilyn Kenny Brown Cars Mustang GT4


Kenny Brown GT-ST (Sport Touring) Mustang 470hp


Sport Touring at its Best!

If you like to drive, I mean really drive; open highways, twisty back roads or canyons and there isn’t quite enough “Sport” in your GT Mustang. Or you want a little more than the factory offers, but don’t want to go all out – a Kenny Brown GT/ST Sport Touring Mustang is exactly what you need.

Kenny’s GT/ST hits all the basics of building your Performance Platform with the “5-Secrets” of his great cars – Chassis, Suspension, Wheels, Tires, Brakes.

  • Chassis: Jacking Rails help firm the chassis as they give you an easy way to jack-up your car, and a precision short throw shifter for toggle-like shifts.
  • Suspension: Kenny upgrades your suspension with Sport Touring ride-height adjustable coil-over springs and shocks.
  • Wheels/Tires: 19x10-inch alloy wheels all round with wide grippy 285/35/19 High-Performance rubber gives you the look and road gripping feel of a true high-performance Mustang.
  • Brakes: Two-piece slotted rotors front and rear improve brake cooling and performance plus gives your Mustang that hot performance track-car look.

Kenny always builds his Performance Platform first before adding any more power and the GT/ST is no exception with Cold-Air Kit, Engine Tune and Sporty Exhaust nudges the power up. Oh, and don’t forget your GT/ST is a genuine Serialized Kenny Brown Mustang.

You will feel amazingly confident in just how well your GT/ST drives with:

  • Better Handling
  • Better Stance
  • Better Sound
  • Better Braking
  • Better Shifting
  • More Performance and a lot Better Looks, just like all Kenny Brown Mustangs to the envy of all your friends and neighbors.

But it doesn’t end there. Just like all Kenny Brown Mustangs, your GT/ST is totally track capable. You can drive it to the track on weekends, impress the hell out of your friends and it drive home smiling all the way.

Horsepower 470hp*

*Horsepower numbers are estimated; all engines are different, and power will vary from car to car.

Mustang GT4 Brake Pads Kenny Brown Cars

Kenny Brown GT4 Mustang - 485hp


A real Grant Touring street performance Mustang to drive. Smooth, crisp, compliant and responsive with incredible driving dynamics and impeccable manners. 

Kenny hits all five of his Performance Platform building secrets, before he adds more power: Kenny’s Grand Sport suspension, upgraded wheels, tires, slotted rotors, sport exhaust and the list goes on. You feel like you own the road, totally connected in your Kenny Brown GT4 Mustang.

However, it doesn’t end there; your Kenny Brown GT4 Mustang is totally track capable. You can drive it to the track on weekends, impress the hell out of your friends and it drive home.  


Kenny Brown GT4/CS (Club Sport) Mustang 520hpGT4/CS (Club Sport) Mustang - Up to 520hp


Engineered to deliver exceptional driving dynamics and dressed to impress at Motorsport Country Clubs and Track Days. The Kenny Brown GT4/CS Mustang is more track-focused with wider wheels, fat sticky tires, bigger brakes, plenty of power (up to 520hp), more down force along with a host of other upgrades; yet still civil enough to drive to the track or out for ice cream with the family. 


Kenny Brown GT4/CSR (Club Sport R) MustangGT4/CSR (Club Sport R) Mustang520hp - 575hp*


Now you’re getting really serious. This is Kenny’s top of the range for street/track day custom Mustangs. Amazing power, even wider wheels, stickier tires, and even bigger brakes, double adjustable shocks with canisters and lots of aero down force - everything you need to totally dominate at the track. If you want an incredible track car, with a feeling of power, performance, control and confidence here it is. And there is still enough adjustability to turn it down a notch or two into an awesome super-hot street monster!




Wicked Fast Supercharged Mustangs

Mustang GT4 Supercharger Kenny Brown Cars

Wicked fast power with incredible driving dynamics describes Kenny Brown Supercharged GT4 Mustangs with completely engineered performance upgrades to all major systems to support the added power.

The Kenny Brown Supercharged Performance Platform includes upgrades to - cooling, suspension, wheels, tires and brakes, with even a little aero for high-speed stability, relevant to the added power from the Supercharger.

Interesting Note: Mustang GT’s are engineered by Ford to handle around 460hp; they weren’t engineered to add another 250hp-310hp. That is why the GT500 cost over $35,000 more than the GT. A Porsche 911 Turbo is around $100k more than the base 911, because both of these the cars are reengineered to support the added power. This is why Kenny reengineers his Supercharged Kenny Brown Mustang's “Performance Platform” power foundation to support all the added power.

Kenny Brown Supercharged Street Fighter Mustang 710hp



Kenny Brown Supercharged Street Fighter Mustangs 710hpThe Kenny Brown GT4/S Street Fighter is Kenny’s answer to those Ford dealerships and others that just throw a big supercharger on a base Mustang and sell them without ANY thoughts about safety or system upgrades to support the added power. Kenny feels that the advertised so called $40k supercharged dealership base Mustangs are dangerous to drive and they are definitely not looking out for your best interest you.

The Kenny Brown GT4/S Street Fighter gives you just enough added upgrades to key systems (cooling, suspension, wheels, tires, brakes) to ensure your Street Fighter can handle the extra horsepower. Plus, it rides, drives, feels, and performs like a Legendary Kenny Brown Mustang.

In a Straight Fight, the Street Fighter will kick a $40K Dealership Mustang’s butt all day long and twice on Sunday.

Kenny Brown GT4/Super-S Supercharged Mustang

GT4/Super-S Supercharged Mustang - 770hp


Wicked fast supercharged power with superb handling, unmatched control and driver confidence for an unforgettable exhilarating and fun driving experience. 

In some sense you can think of the 770hp supercharged Kenny Brown GT4/S Mustang from an engineering perspective, like a Porsche Turbo. When Porsche adds big turbo power to the 911, they basically re-engineer the entire car to support all the added power of the turbo with pretty much bigger, better everything. 

When Kenny adds the fierce power of a supercharger, he doesn't just add a supercharger. He re-engineers the entire car to support the added power with premium performance upgrades to all the major systems.

Where others bolt on a supercharger and maybe a few common off-the-shelf parts, Kenny takes a much, much deeper dive. With custom premium components built to his stringent specifications, all engineered to command and control the potent 770hp with confidence.

Bigger brakes, totally upgraded suspension, bigger better cooling, bigger better wheels & tires, better fuel systems, aero for high-speed stability and the list goes on. All part of the Kenny Brown “Magic” that gives you a fantastic, spine-tingling experience with unmatched driving confidence.      

Build Your Dream Car with Kenny Brown