GT4-RS Mustang

  • Ultimate Max-Performance
  • For Track Day and Country Club Enthusiasts
  • 470hp 5.0 4V TiVCT Coyote Engine
  • Impressive 7.2:1 Power to Weight Ratio
  • More cost effective option to the Porsche GT3-RS
  • GT4 Track Sport Performance Package
  • Tailored to Dominate the Race Track


The Kenny Brown GT4-RS Mustang is a super-premium max-performance Mustang specifically designed as the ultimate track day car that's a more affordable option to the Porsche GT-3RS for motorsports country clubs.  The "flagship" of the GT4 product range, this car has it all and represents the most technologically-advanced, turn-key Mustang ever produced by the company.

With a power to weight ratio around 7.2:1, the GT4-RS Mustang fits nicely into a pretty exclusive group of super sports cars. The GT4-RS is really quick, nimble and inspiring to drive, with incredible handling and eye-popping braking providing huge fun factor on the race track.  In reality, it only looks like a Mustang, because on track it’s in a class by itself, true driving nirvana.  

The Kenny Brown GT4-RS is an extraordinary track car that’s just short of full race, think of it as a very reasonable racecar, with an air conditioner, power windows, and a stereo.  Though the sweet, sweet sounds the GT4-RS makes at full song trumps any stereo. 

Kenny knows from his extensive racing and track day experience that real speed is in the chassis and suspension and that comes through loud and clear, once you take your first turn on track. The GT4-RS features a Coyote 5.0 TiVCT engine with 470 high-revving naturally aspirated horsepower, equipped with a fully-optioned AGS 4.0 Advanced Geometry Suspension System. The GT4-RS is a heavily optioned GT4-CS that comes standard with a plethora of world-class performance and racing options including, Baer 6-piston monoblock calipers with 14-inch rotors, and massive Pirelli Corsa DOT race tires mounted on light-weight Forgeline motorsport wheels, custom engine and transmission upgrades, race cooling system, aggressive exhaust, motorsport aerodynamic package, and a host of other high-tech accompaniments.  Believe it or not, there are even more additional options for this flagship Mustang.

Kenny Brown GT4-RS Mustang conversions are available for 2011-2014 Mustang GT’s with the 5.0L Coyote engine, BOSS 302 Mustangs and Shelby GT500’s, and 2005–2010 Mustang GT’s and Shelby GT500’s.


Content based on a 2012-13 Mustang GT Premium  ALL Track Pack option. Content varies slightly with stock GT, V6 or GT500.

We offer a free design service with many options to further customize your Kenny Brown Mustang to make it your own. It's on the house - extra service and advice with Kenny involved from the start to oversee your project. We can help as little or as much as you would like.  You'll see and we can create a plan that meets your goals and budget… and when you're ready, we'll bring the project to life.  Our design experts can work with you by phone, online or by visiting our Performance Center.

  • HO Engine Pack - 470 HP
    • Ford Racing BOSS 302 Engine Upgrade
    • Air Kit
    • Oil Separators
    • Custom 92 octane track calibration
  • Road Race Oil Pan


  • Stainless steel long-tube exhaust headers
  • Stainless steel cross-over pipe w/ or w/o high-flow Catalysts
  • Stainless steel cat-back exhaust w/ high-flow mufflers


Transmission - Drivetrain
  • Tremec Magnum XL rear-shift 6-speed transmission
  • High-performance clutch and flywheel
  • Aluminum driveshaft


Rear End
  • Custom KB specific torque sensing R-style differential
  • Boss 302 Aluminum Differential Cover
  • 3.73:1 Final drive ring & pinion


  • HD aluminum radiator
  • Positive flow radiator ducting
  • Engine oil cooler


High Performance Brakes
  • Baer Extreme+ 6-piston monoblock fixed-mount pin-drive calipers front & rear
  • Stainless steel brake lines
  • 14" x 1.25" ventilated slotted rotors front & rear
  • High temperature brake fluid
  • KB Front brake cooling ducts (fascia to spindle)
  • Hawk KB specific racing brake pads front & rear


Wheels & Tires
  • MonoBlock Forged Race Wheels -- 18”x19” front and 18”x19” rear
  • Pirelli PZero Corsa DOT race tires -- 295/30/R19 front 305/30R19 rear


Chassis Support
  • KB Jacking Rails
  • KB Extreme Matrix Chassis Support System
  • Rear Shock Tower Brace
  • KB Club Sport Cage


  • Kenny Brown AGS 4.0 Track Sport Suspension
    • Advanced Geometry Suspension System
    • Adjustable front Sway Bar


Track/Sport Springs and Shocks
  • KB/Paul Brown Club Series JRZ Single Adjustable Shocks
  • KB selected Eibach spring rates for specific driver style
  • Adjustable ride height


  • Side Skirt Splitters
  • Paul Brown Racing Heat Extracting Carbon Hood
  • Paul Brown Club Sport Rear Wing
  • Front Splitter w/fender air dams
  • Custom Graphics


  • Driver’s left foot dead pedal
  • Club Sport Seats
  • 6-Point hybrid harness belts
  • Battery relocation to rear


Serialization & Graphics
  • Dash plaque & Under hood production plaque
  • Special exterior GT4-RS graphics package
  • Log Book, set-up, history & maintenance info


  • Set-up class for you or your crew on your car
  • Test day with Kenny helping set up your car
  • Driver Coaching with Kenny
  • Please call our Performance Center to talk with one of our design pros about all the options available to further custom tailor your Mustang for your specific requirements.  Call 317-396-2768 or email to


2013 Kenny Brown GT4-RS Custom Conversions Starting at $ 49,950

Final cost will vary as each Kenny Brown GT4-S is hand build, bespoke with content specific to the individual’s needs and budget.

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