The BMW M3 has had a variety of engines under its hood since the performance model's inception in the latter half of the 1980s. It originally came out with a small four-cylinder engine before graduating to an inline-six, and eventually, a meaty V8. With downsizing in full swing, the M3 will never go back to an eight-cylinder engine as today's inline-six will likely be hybridized before succumbing to the impending EV assault.

In direct contradiction to the less-is-more trend, this E46 coupe sold in the 2000s has been subjected to an impressive engine transplant courtesy of Dutch shop Autoservice Procar. Gone is the OEM inline-six, replaced by a naturally aspirated 5.0-liter V10 sourced from the mighty M5 E60. It pumps out a healthy 507 horsepower and 520 Newton-meters (384 pound-feet) of torque, which is quite an improvement over a stock M3 from that period.

But wait, there's more. Aside from cramming a larger engine, BMW specialist Autoservice Procar also yanked out the original gearbox. Instead of having the OEM six-speed manual or the dreaded SMG automated manual transmission, the M3 E46 featured here has a seven-speed, dual-clutch automatic of unknown origins, but possibly borrowed from the car’s successor, the M3 E92.

The heavily modified sports coupe was put through its paces on an unrestricted section of the Autobahn during some amazing acceleration tests, all the way up to 186 mph (300 km/h). Sebastian Vettel might say speed limits are a "no-brainer" on Germany's glorious highway, but we would certainly miss this type of video in which a special car is going at full tilt.

It's especially true when the featured vehicle has a screaming V10, singing its sweet tune at more than 8,000 rpm while the driver literally uses the car’s whole speedometer. This package seems just about perfect for a lightweight, two-seater supercar, one that unfortunately never happened and it’s too late in the game to expect such a flagship sports car from BMW.

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