Even in stock form, the latest generation BMW M340i xDrive is no slouch. Its 3.0-litre turbocharged petrol engine produces a healthy 382 bhp (285 kilowatts) and 369 pound-feet (500 Newton-metres) of torque, which are channelled to all four wheels for a 0 to 62 miles per hour (0-100 kilometres per hour) acceleration in just 4.4 seconds. What more could you ask for? More power, of course.

That’s where the folks from G-Power come to make your wildest fantasies become true. How about a 3 Series-based estate with more power than the M3 (F80)? The tuning company has the answer but we’ll get to that in a minute - first, let’s take a look at the firm’s different tuning packages for the G20/G21 duo in M340i xDrive form.

Gallery: BMW M340i xDrive by G-Power

For starters, there’s the entry-level GP-420 package, which boosts the output to 420 bhp (313 kW) and 442 lb-ft (600 Nm). That’s purely a software massage for the inline-six engine with no hardware upgrades. If you want more power, you’ll have to go for the GP-470 kit, which also includes a performance exhaust system with a new catalytic converter for a peak power of 470 bhp (350 kW) and 479 lb-ft (650 Nm) of torque - already above the M3 (F80) levels. 

This brings us to the flagship offering - the so-called GP-510, which - as its name implies - increases the output to the incredible 510 bhp (380 kW) and 509 lb-ft (690 Nm). That’s possible thanks to a new engine management software and a bigger turbocharger, in addition to the previously mentioned hardware upgrades. G-Power even offers to unleash a higher top speed of 186 mph (330 kph).

In terms of acceleration, the base package promises to cover the 0-62 mph (0-100 kph) run in 4.0 seconds, while the GP-470 will go below the four-second mark (3.8 seconds). A further 0.1 seconds improvement comes with the most expensive option.