The 2006 BMW 525i four-door sedan was powered by an all-new 3.0-liter six-cylinder engine that produced 215 horsepower, an increase of 31 horsepower over the previous year's engine. The additional power was courtesy of such upgrades as variable valve timing and electronically controlled engine cooling. A six-speed manual overdrive transmission was standard, while a six-speed automatic was available as an option.

As was the case with prior models, test drivers didn't particularly like the layout of the controls or the 525i's fuel economy, but those two setbacks were overshadowed by checks in the "pros" column: steering, handling, ride, build quality, and interior materials.

Standard features for the 2006 525i included a power glass sunroof, multi-zone climate control, power windows with remote window operation, a power-adjustable driver's seat, power-adjustable headrests, wood interior trim, power exterior mirrors, a leather-trimmed steering wheel with controls for the audio and cruise control systems, an anti-theft alarm system, and an AM/FM stereo system with an in-dash CD player.

Four-wheel anti-lock brakes, traction control, stability control, a tire pressure monitoring system, and 17-inch alloy wheels were also part of the package.