There’s something undeniably exhilarating about pushing the limits of what’s possible. Whether it’s the raw numbers on a dyno sheet or the feeling of an engine coming alive under load, tuning is about unlocking hidden potential. Our latest dyno testing session focused on refining our tunes for BMW’s most formidable M cars—the M2, M3, M4, and M8.
Each one of these beasts exceeded our expectations, but none more so than the M2, which took home the title for the biggest power gain of the day with an incredible 126 bhp increase from stock.
With the entire day covered by YouTuber Petrol Poodle, his upcoming video will help translate the data we collected into something the wider enthusiast community can fully appreciate. But for those who want the full breakdown of what went down, here’s our in-depth look at how each of these cars performed and what we learned along the way.
BMW M2 – The Pocket Rocket with a 126 BHP Surprise
Stock Figures: More Than Meets the Eye
The BMW M2 has always been a fan favourite. Compact, aggressive, and with all the right M-car ingredients, it’s a driver’s dream. The example we tested came in stock at 466 bhp and 580 nm of torque from its turbocharged inline-six. While those numbers sound impressive on paper, we suspected there was more to be had—and we were right.
Tuned Figures: A Record-Breaking Gain
After refining our tune and running multiple dyno pulls, the results left us stunned. The M2 saw an increase of 126 bhp, bringing its new total up to a staggering 592 bhp and 714 nm of torque. This wasn’t just a marginal improvement; it was a full transformation that directly related to the raw feeling of unlocked power on the road.
Post Tune Reflection: How the Tune Changed the M2
The difference wasn’t just noticeable in the numbers—it was felt in every aspect of the drive. The power delivery became sharper, the throttle response more immediate, and the car's ability to pull through the rev range was night and day compared to stock. The M2 went from being a fast, agile coupe to something that could confidently hang with much bigger, more powerful machines. The implementation of the power also changed, instead of being throttled, each gear change becomes a challenge of taming the untapped horsepower of the car. With the right conditions, the M2 goes from being a planted tuning marvel into a precisely wound thread weaving down the road, planted but free to release the horsepower produced.
BMW M3 – The Balanced Performer Gets Sharpened
Stock Figures: M Power Refined
The G80-generation BMW M3 represents everything that makes the M division great—precision engineering, brute force, and everyday usability. Our test car, in stock form, produced 523 bhp and 692 nm of torque, already making it one of the most powerful M3s to date. But, as always, we knew there was more to be unlocked.
Tuned Figures: Unlocking More Mid-Range Punch
Once our optimized tune was applied, the M3 put down 634 bhp and 848 nm of torque on the dyno. While it didn’t see the same extreme gains as the M2, the improvement was undeniable—particularly in the mid-range, where the torque increase made an enormous difference to real-world drivability. Allowing the car to be light and nimble but also planted and ready to power through any driving condition.
Post Tune Reflection: How the Tune Changed the M3
Post-tune, the M3 felt like a completely different animal. The added power made it more ferocious without sacrificing its composure. The mid-range surge made overtakes effortless, while the sharper throttle response gave it a more immediate and aggressive feel on the road. This M3 now had the power to match its track-ready chassis dynamics. Compared to the M2 it felt like the further refined brother, utilising the 4-wheel-drive system to accurately put down its power. Instead of being on the cusp of blowing the tyres off the M3 was allowed to show the true performance it could give while also enhancing the already incredible vehicle.
BMW M4 – The Ultimate Grand Tourer Turned Savage
Stock Figures: A Heavy Hitter from Factory
The M4, essentially the coupe variant of the M3, shares the same 3.0-litre twin-turbo S58 engine but boasts the formidability and aggression of being the M3's big brother. Our test car produced 523 bhp and 629 nm of torque on the stock tune—mirroring the M3.
Tuned Figures: An M4 That Can Keep Up with Supercars
With our tune applied, the M4 cranked out 634 bhp and 848 nm of torque, pushing it along with the M3 well into supercar-rivaling territory. The additional power didn’t just show up in peak figures—it was evident in how much harder and more urgently the car pulled at any rpm as well as producing an untapped raw feeling of pure power being driven into the road.
Post Tune Reflection: How the Tune Changed the M4
While the M4 was already a formidable machine, the extra power transformed it into something truly explosive. Power delivery was seamless, and the increased torque made full power pulls almost effortless. What was once a refined high-performance coupe was now an absolute weapon on both road and track. It now can boast the raw appeal that enthusiasts want whilst maintaining its versatility of being the ultimate tourer with a motorsport heart.
BMW M8 – The Untamed Beast Unleashed
Stock Figures: BMW’s Luxurious Supercar
The M8 is a different kind of M car. It’s big, luxurious, and brutally fast even in stock form. Our test car produced 613 bhp and 810 nm of torque making it the most powerful M car ever produced. But we had a feeling there was still untapped potential within that twin-turbo V8, the same twin-turbo V8 shared by the new BMW M5.
Tuned Figures: A True Monster Unleashed
Post-tune, the M8 broke past our expectations and hit 682 bhp with 953 nm of torque, putting it in the range of nipping at the heels of conventional supercars. This is more impressive given the original intentions of the car as a high horsepower, performance, luxury grand tourer. The car now accelerated with a level of brutality that was borderline terrifying in the best way possible, effortlessly planted to the road.
Post Tune Reflection: How the Tune Changed the M8
With the extra power, the M8 became something entirely new. While it retained its grand touring comfort, it now had the performance to keep up with exotics that cost twice as much. The linear power delivery and immense torque meant that every squeeze of the throttle delivered relentless acceleration unlocking a new profound level of respect for the raw power of the M8. This was an M car taken to its ultimate form, combined with its already striking appearance, the M8 became part of M performance royalty.
Final Thoughts & What’s Next
Our dyno testing day confirmed what we’ve always believed—BMW M cars have enormous untapped potential just waiting to be unlocked. Every car we tested exceeded our expectations, with the M2 being the standout performer of the day with its astonishing 126 bhp gain.
Each tune not only improved the power figures but fundamentally enhanced the driving experience, making these already incredible cars even more potent. The M3 and M4 became sharper, the M8 became an untamed beast, and the M2? Well, it became something that can punch well above its weight.