• 2015 BMW M4 Special Edition GTRS4 By Vorsteiner

    What can make the M4 even better? How about a carbon-composite wide-body kit?

The 2015 BMW M4 saw lots of love at SEMA this year, and for good reason. The German special has all the right roots to make it quite the tuner car for those daring to mess with something so good out of the box, like a twin-turbocharged, 3.0-liter, inline-six motor putting out a healthy 425 horsepower through a six-speed manual gearbox (don’t forget the optional seven-speed dual-clutch automatic for those afraid of more than two pedals). Then there’s the suspension, which is geared with obvious intention toward track usage over previous models, with “play-free” ball joints and elastomeric bearings, a CFRP strut-tower brace, and a rear axle that’s bolted directly to the rear subframe. The result is a car that simply begs for apexes.

LA-based body kit designer Vorsteiner, which produces aftermarket aero pieces and wheels for high-end imports such as Porsche, Ferrari, and Bentley, is celebrating 10 years of business, and as a gift to itself and anyone who enjoys full carbon-composite, wide-body Bimmers, it created the M4 that lays before you. With a focus on mixing an organic look with functional performance, the design process started earlier in the year, culminating with a debut in Vegas in October 2014.

After finalizing the overall design, Vorsteiner 3D scanned the stock coupe, then overlaid the renderings to produce quick CNC prototypes to aid in development. The result, as you can clearly see, is pretty amazing. The lines pay homage to BMW’s touring car racing heritage, but keeps things within the realm of street usage. Oh, and did I mention that it’s full carbon composite?

Click past the jump to read more about the BMW M4 Special Edition GTRS4 By Vorsteiner.

  • 2015 BMW M4 Special Edition GTRS4 By Vorsteiner
  • Year:
  • Make:
  • Model:
  • Engine:
  • Horsepower @ RPM:
  • Displacement:
    3.0 L
  • 0-60 time:
    3.7 sec. (Est.)
  • Top Speed:
    186 mph (Est.)
  • Price:
    100000 (Est.)
  • Price:
  • car segment:
  • body style:


2015 BMW M4 Special Edition GTRS4 By Vorsteiner High Resolution Exterior
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Vorsteiner claims the new fenders add two inches of width per side up front and three-and-a-half inches per side out back which is sizable, but not totally crazy compared to some of the other cars lurking around SEMA. The fenders also incorporate functional cooling ducts for the brakes, a feature often overlooked on custom wide-body kits. Complementing the new corners is an upgraded front bumper with integrated splitter, aero blade side elements, and a new rear bumper with an integrated rear diffuser. All are made from lightweight carbon fiber and coated in BMW’s factory Austin Yellow Metallic paint.

Taking advantage of the extra real estate under the fenders, we find custom three-piece forged wheels designed in-house and measuring in at 20 inches in diameter, with 10.5 inches of width up front and 13.5 inches in the rear. The cherry on top is on the rear, which features chrome trunk badging and quad custom-finished 90 mm (3.5-inch) exhaust tips.


Inside, you’ll find the stock setup mostly untouched, with the exception of a Vorsteiner-embroidered floor and trunk mat set. Everything else, like the copious M badging, race-inspired seats, and leather-wrapped multifunction steering wheel, are all retained. While I would like to see more, it’s not a big deal. I like the interior of the M4 just fine.

Drivetrain and Suspension

2015 BMW M4 Special Edition GTRS4 By Vorsteiner Exterior
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The drivetrain upgrades are pretty mild as well, at least compared to the modifications made to the exterior, as the only mod is increased boost via ESS Tuning’s E-Tronic ECU retune. This retune increases output to an impressive 550 horsepower and 560 pound-feet of torque, all without any splicing or additional adjustments.

Lowering the stance is KW Suspension’s sleeve kit, which maintains BMW’s Dynamic Drive features, like active roll control and adjustable rigidity settings. Those larger wheels accommodate large tires as well, with Pirelli’s P Nero rubber measuring 275-mm width up front and 345-mm width out back.


2015 BMW M4 Special Edition GTRS4 By Vorsteiner High Resolution Exterior
- image 580956

Starting at $64,200, this luxury import just gets pricier as the option list is filled. But beyond BMW’s extras, anyone looking for their own carbon wide-body M4 from Vorsteiner should consider tacking on an estimated $25,000 for just the raw bumpers and fenders. Then there’s the paint, interior floor and trunk mat set, the wheels, the tires, the suspension and engine upgrades… and you’re probably looking at a car costing you well over $100,000.


2015 BMW M4 Special Edition GTRS4 By Vorsteiner Exterior
- image 575288

Wide-body kits are everywhere at SEMA, but this one looks particularly well done. The fact that it’s carbon fiber makes it even better. The drivetrain and suspension upgrades are more or less an afterthought, but that’s okay; we understand this is a car that’s all about making its presence known on the show floor, and it does that with style and poise. If you like the M4, but want something unique to throw six-figures at, this might be the winner for you. Just avoid those low driveways; carbon fiber isn’t exactly malleable.

  • Leave it
    • Could use additional suspension upgrades to take advantage of extra rubber
    • Few interior upgrades
Jonathan Lopez
Jonathan Lopez
About the author

Press Release

Vorsteiner is celebrating our 10 year anniversary this year and to commemorate this occasion we have developed a very special limited edition vehicle, code named GTRS4 debuting at the 2014 SEMA Show. The GTRS4 is a full lightweight carbon composite wide body conversion that is based on the 2015 BMW M4 coupe. The design and development of the GTRS4 started early this year as there were countless hours of testing and modeling that took place.

2015 BMW M4 Special Edition GTRS4 By Vorsteiner Exterior
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Design of an Icon:
The idea was first conceived on a blank sheet of paper where our designers took into the consideration the previous historical wide body editions such as GTRS3 based on the E92 M3, to show a lineage in both Vorsteiner design language, functionality and performance.

Our designers focused making the design organic to the original body lines of the car while retaining full functionality & everyday drivability of the vehicle. It was not enough just to make the widest possible fender as it was also dictated by the ability of the wheel to turn while under load at high or low speeds.

We also wanted to ensure the design paid tribute to M3 racing heritage and lineage while still maintaining the minimalistic Vorsteiner concept,

The Beginning of a Legend:
Once the design was sketched and finalized on paper we 3D scanned the entire factory body using Blue Light Laser Technology. With our 3D renderings, we digitally surfaced the new body panels and created CNC rapid prototypes to fit on the vehicle.

The most crucial step was the rear quarter panels as it was very important to create a perfect contour. In order to effectively create, readjust and improve this shape, our in-house master craftsmen utilized traditional clay modeling to achieve seamless and fluid proportions.

Form Follows Function:
From the original launch of the development process, our design and engineering team worked in tandem to ensure the wider fenders and wheels were functional. We strategically crafted air ducts for optimal cooling towards the front brakes, while paying attention to aerodynamic ventilation for the inbound air to exit.

The front fenders have a total span of 4 inches while the rear quarter panels sit 7 inches wider than it’s original form. We’ve specially designed 3-Piece Forged wheels in 20x10.5J and 20x13.5J respectively to fit the 275 and 345 width tires.

The vehicle is also fitted with Pirelli’s signature P Nero tires for optimal traction and performance. To add to the stance, our GTRS4 features KW Suspension’s sleeve kit allowing for height adjustment as well as keeping the original BMW Dynamic Drive features. Adding to the performance, simplicity, and versatility, the GTRS4 is upgraded using ESS Tuning’s E-Tronic for an impressive 550hp to the crank.

2015 BMW M4 Special Edition GTRS4 By Vorsteiner Exterior
- image 575288

The Special Edition GTRS4 Package Includes:
· Carbon Fiber Front Bumper with an Integrated Front Splitter Element
· Carbon Fiber Wide Front Fenders with Ventilation (2 inches wider each side)
· Carbon Fiber Aero Side Blade Elements
· Carbon Fiber Wide Rear Fenders (3.5 inches wider each side)
· Carbon Fiber Rear Bumper with an Integrated Rear Diffuser Element
· Vorsteiner 90mm Quad Exhaust Tip Finishers (Options: Brushed | Diamond Black)
· Vorsteiner Embroidered Colored Floor & Trunk Mat Set
· Vorsteiner Chrome Trunk Badging
· GTRS4 Forged 3-Piece Wheels, 20x10.5J | 20x13.5J in Gloss Brushed Shadow

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