BMW's G01-generation X3 represented a meaningful step forward for the nameplate, and the M40d sits at the top of the diesel range as the version that makes the most complete argument for the whole lineup. The straight-six diesel under the bonnet produces 340 HP and 700 Nm of torque, which is a substantial figure for an oil-burning SUV of this size, and it translates into a 0 to 100 km/h time of 4.9 seconds alongside a fuel return of 17.9 km/L that makes long-distance running genuinely economical. All-Wheel Drive distributes that output with confidence, while the M Adaptive Suspension and Variable Sport Steering give the chassis a precision and body control that lifts it clearly above the standard X3 in how it responds to the driver. The Phytonic Blue Metallic exterior is a considered choice that suits the M40d's understated character well, and the Panoramic Sunroof and LED headlights complete a clean, purposeful presentation. Inside, the Cognac Vernasca leather cabin is well-appointed and properly comfortable, with BMW Live Cockpit Professional bringing a 12.3 inch digital instrument display and 10.25 inch central touchscreen, supported by a Harman Kardon surround sound system, wireless Apple CarPlay and Android Auto, 360 degree view cameras, ambient lighting, and a powered tailgate. As a package, this X3 M40d offers a level of specification and dynamic ability that is difficult to match at this size, and it is presented in one of the stronger configurations the model was offered in.