BMW M850i Gets More Power Than a Standard M8 for About $2,770

The Last BMW Grand Tourer

BMW has no problem selling coupes, but the bigger they get, the harder they become to find new homes. For instance, the 4 Series, both in two and four-door guises, sell well. Even the 3 Series Coupe predecessors did great back in the day. But if we’re talking grand tourers, it’s a different story.

The first 6 Series was a smash hit, but later generations weren’t exactly runaway successes. The first 8 Series didn’t light up the sales charts, and the same could be said about the recently discontinued second-gen model. Still, the big coupes have their respective fanbases, but it’s not enough to justify BMW to keep on building these.

The M8 Coupe was canned in 2025, while the other versions stopped production earlier this year. You can still buy the latter new while stocks last, but the 8 Series is gone for the second time in history, and it’ll be a long time before BMW even reconsiders bringing back a large coupe.

No Shortage of Tuning

Still, both manage to capture enough of a following for it to gain loads of aftermarket support. Of course, it helps that both the M850i and M8 have the same 4.4-liter engine block that powered V8 5 Series, 7 Series, X5, and X7 models. Economies of scale work in the tuning scene, too.

G-Power is one of the many companies that will be more than happy to extract more horsepower from these engines. It has power kits for the M8, but those who missed the boat and got an M850i instead need not worry. That’s because the tuning firm also has a package that gives the junior M car even more power than its more potent brother.

Packing the Goods

Meet the G-Power M850i Bi-Turbo. It benefits from the GP-620 performance software, and it gives the car 620 metric horsepower. Translate that to imperial, and that’s 612 hp, which 12 hp more than a standard M8. It’s still a little behind the Competition version, but it the tune gives it a 70 lb-ft torque advantage over the factory version for a total of 623 lb-ft.

The performance gains are even more evident when compared to a stock M850i. Left untouched, the coupe makes 523 hp and 553 lb-ft right out the box. With the software upgrade, it gains 90 more horses and 70 lb-ft. The power pack alone costs €2,495, or roughly $2,770.

It doesn’t sound bad at all considering the gains, although it’s €495 ($550) for the speed limiter increase to 186 mph. It’s another €238 ($264) for an upgraded air filter, and another €395 ($438) to get the digital cluster to read up to 330 km/h or 205 mph. Add all of those and the total bill will set you back €3,623 or a little over $4,000. Also, for those who want to make the car stand out from the outside, G-Power has that covered, too.

Other Options

You can add a G-Power sport exhaust system for €4,760 ($5,280), along with the option to upgrade the downpipes in one of three ways which is another €4,760/$5,280 extra for the most expensive option. The carbon hood will set you back €7,140 ($7,920), while the carbon wing goes for €3,392 ($3,696). If you fancy the carbon steering wheel with shift lights, that’s €3,750 ($4,160), and the 21-inch G-Power Hurricane RS wheel set is another €8,806 ($9,769).

The total cost of the other options mentioned just above is €32,608. Include the power pack, speed limited increase, upgraded speedometer, and air filter, and the whole package goes for €36,231 or around $40,210. It’s a lot of money, but there is good news here. You can just get the power pack plus all the other minor enhancements and leave the rest of the exterior alone to make it a sleeper.