The BMW 5 Series could be the best vehicle within the entire BMW lineup right now. Following its most recent update, the G30-generation 5 Series looks great, is both enjoyable and comfortable to drive, and is potent in virtually any guise. One of the most intriguing - and underrated - versions is the V8-powered M550i which sits below the M5.

Its 4.4-liter twin-turbo V8 is an absolute gem and enough to get the large sedan from 0 to 60 mph in under four seconds. It makes the M5 seem truly superfluous as the M550i is only a few tenths slower to 60 mph. RaceChip decided to hook the sedan up to the dyno to see if BMW's claimed outputs are accurate before tuning it for even more grunt.

The M5 previously proved to be even more powerful than BMW claims, so would the M550i follow suit? Well, RaceChip's results show that the 2020 M550i produces 526 horsepower and 568 lb-ft of torque. BMW's official numbers are 523 hp and 553 lb-ft. That's pretty close but, like the M5, it seems that these BMW engines are producing more torque than claimed.

Next, the guys treated the M550i to a tune, and the results were certainly impressive. The M550i was now pushing out 585 hp and 645 lb-ft. Compare those figures with the M5's 600 hp and 553 lb-ft of torque, and it's clear that a tuned M550i can give unsuspecting M5 drivers a real scare.

In terms of performance, RaceChip's tune shaves 1.28 seconds off the M550i's 62 to 124 mph time, which they claim is quicker than a Porsche Panamera Turbo and a Lamborghini Urus.

Although the M550i misses out on the M5's specific suspension tweaks and visual add-ons, it crucially gets BMW's rear-biased xDrive system, which makes it possible to handle all that power. Besides, not everyone likes the in-your-face approach of the M5; the sleeper M550i is less pretentious but almost as quick. Is the M550i - stock or otherwise - the pick of the 5 Series range? It certainly makes a mightily strong case for itself.