OEMs obsess over special edition releases, complicating the market to an annoying level. From supercar manufacturers like McLaren to the enthusiast-focused models from Subaru and Toyota, these manufacturers made a strong business case for limited run model trims. Simply throw in a few carbon panels, use a different color thread for the interior stitching, and program in five extra horsepower. Stamp a "# out of 500" plate on the dash and you can boost your profit margin by a significant percentage. This isn't always the case, but still the truly special limited edition models are too few and far between. BMW's 2016 M4 GTS stands as one of the few that delivered plenty of reasons to call it a special rarity. Even better, BMW knew their audience when it came to the M4 GTS. This was not a model to be purchased and added to a collection to sit for decades, awaiting a high bidder in the future. The M4 GTS is an OEM-made track car, arriving from the factory with most of the modifications that any active track day driver would have installed anyway. The best part is that the customers recognize this, and instead of leaving the car at home in hopes of price appreciation, they're wringing them out on the race track.
Only 700 examples of the M4 GTS came out of the factory and only 300 made it to the States, making it a sought-after rarity among the track day crowd. David Ishida of Southern California managed to get his hands on one of these few in the summer of 2021, with the intent to use it exactly for its primary purpose. He sold his E46 M3 track build to move into this newer and higher performance model, his reason being "the potential future value proposition since it was produced in such low numbers, and I really liked that it was what BMW's M Division considered to be their most track-focused factory-built road-going car. I knew it would be comfortable enough to drive to the track and plenty of fun on track, so it seemed like a natural progression from the E46." Beyond just tracking for fun, David regularly competes in the CSF Bimmer Challenge, a BMW-focused time trial series hosted by Speed Ventures that spans racetracks throughout California with an additional stop at Las Vegas Motor Speedway. The Bimmer Challenge series offers multiple levels of competition, welcoming builds of all kinds and drivers of all levels. Given that David aimed to compete in this series with his M4 GTS, he still planned to modify it from factory form to increase its competitiveness within his race class.
BMW's Factory-Made Track Car
BMW made the M4 GTS for people like David, offering a street-legal track machine in the form of a stripped down M4. BMW pulled many parts out for weight savings on this model, equipping carbon fiber and lightweight pieces in their place. Much of the interior trim offers weight-saving parts with a minimal racecar look, utilizing carbon fiber in many areas throughout to enhance the aesthetic further. This weight-saving concept extends to the carbon fiber reinforced plastic roof, hood, splitter, and diffuser. These features and more keep the weight down in order to take full advantage of the turbocharged 3.0-liter inline-six that produces nearly 500 horsepower and 450 lb-ft of torque. Ishida recognized these factory-equipped upgrades and their benefits for his use case, "I loved the strong power delivery of the in-line six twin turbo with water injection, super fast shifts from the DCT, and even the sound of the stock titanium exhaust wasn't terrible given how the S55 engines generally do not sound good. It was convenient having the roll bar installed from the factory so all I had to do was swap in some Sparco bucket seats and six-point harnesses." He extended extra thanks to Sparco, as they helped him acquire the interior safety items including the QRT-C seats which perfectly match the car, all while supply chains everywhere were suffering due to the COVID-19 pandemic. The M4 GTS comes equipped with three-way manually adjustable KW Clubsport coilover suspension, allowing you to tune the car to specific tracks, driving styles, and car setups. Lightweight M carbon ceramic brakes sit at each corner to offer excellent deceleration with high heat tolerance, adding further to the car's focus on track use.
Braking And Handling Upgrades For The 2016 BMW M4 GTS
While there was a lot to like about the M4 GTS in factory form, David had ideas in mind for some changes early on. Despite the carbon ceramic brakes' performance capability, they would eventually bring running costs way up. In order to save himself from pricey brake services, including $4,000 per rotor, he switched the car over to M2C iron rotors and smaller AP Racing brake calipers. This saved him money on the running costs while allowing him to swap out the 19-inch and 20-inch staggered wheels in favor of a square 18x11-inch setup. Although David appreciated the car's overall look, he wasn't a fan of the original rear wing and endplates. He installed larger endplates and taller wing stands early on, but this didn't last long as he changed it over to the larger and more effective GT4 rear wing.
Given his goal of competing in the Bimmer Challenge series, David found himself diving deeper than originally intended. He continued on with more modifications to maximize the car's capability within the rules of his competition class. Since the car already produced plenty of power and torque, he focused primarily on handling performance changes. Ishida mapped out a new setup for the car, "Aesthetics and mild track prep were easy and these were where the original plan ended. Things got a bit more involved when I decided to swap out all the kinematics for spherical arms as well as the spring rates, rear weight jacks, and camber plates." A common failure point on the M4 GTS resides within the billet front knuckles, where cracks form at the strut tube pinch points. David discovered that BMW offered an updated knuckle to fix the cracking issue, and that the revised knuckle simply had some extra material shaved off to lessen the stress point. Saving himself a few thousand dollars, he made his own updated part by digging the dremel out of his toolbox and shaving down the material on his own. Although he made multiple changes to the suspension system, David felt no need to change out the KW Clubsport 3-way coilovers as they provided plenty of performance to complement the car.
Finishing Touches Before The Track Attack
A year and a half into this project, and David feels like it's very nearly finished. "I don't ever plan to strip out the interior to get weight down as I think the factory fitment of the roll bar, rear seat delete, and composite door cards are a large part of the car's appeal." So little remains on Ishida's to-do list, "more tire and wheel setup changes, potentially an exhaust, and maybe down the line a KMP steering wheel to replace the stock wheel and airbag. I don't plan to tune it or do any bolt-ons to increase power as I think the 500 horsepower is a nice spot for this car and for me." For his situation, this lightly modified M4 GTS achieves David's goal of a double-duty street and track car as it excels at both. It even helped him earn 2nd place in the championship in his first season with Bimmer Challenge, complemented by a win at Auto Club Speedway among multiple podium finishes throughout the year. David plans to hang onto this M4 GTS for a long time as it checks off every box for what he was looking for. He's interested in other projects down the road like an F80 M3 daily driver and similar, but for now his focus lies in perfecting the M4 GTS in his garage for extra track performance without sacrifice to its streetability.
David would also like to extend special thanks to Rob at Chewerks for his help tuning the car's setup, David of Q Designs for the PPF job, Luciano of Next Level Race Shop for allocating the OEM M4 GT4 wheels and suspension components, Duane of R Compound for his tire help, and "Type R Jose" for being a strong competitor and as a result extra motivation to aim higher. Above all else, he thanks his wife for "putting up with my long hours in the garage and for allowing me to continue to procure parts and tires for the car," and his dad for the inspiration, experience, confidence, and mechanical knowledge he passed down.