At a time when most manufacturers are pouring their development money into electric cars and endless iterations of crossover vehicles, Mazda still sees room to push the limits of what a four-door sedan can be.

Need proof? Take a drive in the heavily updated 2018 Mazda6.

This mid-size car was already one of my favorites thanks to the many things it does well: fuel efficiency, styling, cabin design and—above all else—driving dynamics that make it feel more like a pricey European sports sedan than an affordable family runabout.

Now it's moving into two territories where family cars, especially ones at this price, rarely tread.

One is luxury, seen most clearly on the new Signature trim level I tested. With soft Nappa leather, supple UltraSuede inserts and gorgeous sen wood, a material used in Japanese drums, guitars and furniture because of its toughness and subtly beautiful grain, the top-end Mazda6 feels like it belongs in a luxury-brand showroom.

Of course, looking like a luxury product doesn't matter if it doesn't drive like one, too. The new Mazda6 has a long list of subtle changes that help to keep unwanted sounds and vibrations out of the cabin.

Thicker floor panels, smaller gaps in body panels, quieter tires and suspension tuning, laminated front glass and more carpeting and insulation all add up to a noticeably quieter highway ride. That fixes one of this car's few weaknesses from last year.

The other new territory improves a strength: sporty handling.

Mazda, more than any other mainstream brand, aims to offer the same exciting, refined sensations you get from BMW, Mercedes-Benz and Audi cars, only at a more attainable price.

Last year's model already offered sparkling steering, brake and suspension feel, but this year there is a new engine choice that makes everything feel a notch better. The 2.5-liter turbocharged four-cylinder—very similar to the engine that powers Mazda's big, three-row CX-9 crossover—is now available in the much smaller, lighter Mazda6.

This new engine generates 250 horsepower and, more critically, 310 pound-feet of torque to make it move with sports-car quickness.

Refreshed technology keeps things interesting in the cabin. While I'm personally most excited about the availability of Apple CarPlay and Android Auto for connecting smartphones, other available changes include:

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[naviga:li]A new Mazda Connect infotainment system with an eight-inch touchscreen display.[/naviga:li]

[naviga:li]Ventilated front seats to keep the surfaces cool in hot weather.[/naviga:li]

[naviga:li]A reconfigurable seven-inch display behind the steering wheel.[/naviga:li]

[naviga:li]A 360-degree monitor that shows a bird's eye view when parking.[/naviga:li]

[naviga:li]A full color Active Driving Display projected on the windshield instead of the awkward pop-up reflector in previous models.[/naviga:li]

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Redesigned seats and a number of exterior changes make this a surprisingly thorough update for a vehicle that has already gotten two previous overhauls in the last five years.

Pricing starts at $21,950 for the Mazda6 Sport trim with a manual transmission or $23,000 with an automatic. It tops out with the luxurious Signature line at $34,750.

INFO BOX

2018 Mazda6 Signature

$34,750

Options: Cargo mat ($75), Soul Red paint ($595), scuff plates ($125).

Price as tested (including $890 destination charge): $36,435

Wheelbase: 111.4 in.

Length: 191.5 in.

Width: 72.4 in.

Height: 57.1 in.

Engine: 2.5-liter turbocharged four cylinder (250 hp, 310 ft. lbs.)

Transmission: Six-speed automatic

Fuel economy: 23 city, 31 highway

RATINGS

Style: 9

Performance: 9

Price: 8

Handling: 9

Ride: 8

Comfort: 7

Quality: 8

Overall: 9

Why buy it?

Updates for 2018 make an already strong sedan even better. Its new turbocharged engine and luxurious Signature trim level take it into new performance and luxury territories.