2025 Kia K4 GT-Line First Test: How Fast Do You Wanna Go?

Although it still has room to improve, the turbocharged version of the K4 compact sedanlooks way hotter and features an equally handsome cabin with enough modern tech to rival the best in the class—and even classes above. You also get plenty of space and an above-average driving experience with the turbo, even if the Honda Civic is better in most ways.

Yet that’s not representative of the K4 lineup as a whole, as most trims feature the naturally aspirated engine. And that's why we’re testing this non-turbo K4 GT-Line.

While it’s not the top model in the range (that’s the Turbo GT-Line), the GT-Line is just one rung down. It features a 2.0-liter inline-four and CVT instead of a 1.6-liter turbo-four and eight-speed automatic transmission.

Should Have Kept the Gas Tank

The base engine carries over from the Forte, and it predictably returns similar fuel economy. Most nonturbo 2024 Fortes returned 39 mpg highway, identical to the 2025 K4. The 2.0-liter K4 gets 29 mpg in the city, but the tank size shrunk from 14.0 to 12.4 gallons.

For comparison, the nonhybrid 2025 Toyota Corolla FX sedan—which also features a 2.0-liter engine, CVT, and FWD—gets 31 mpg city and 39 mpg highway. With its 13.2-gallon tank, though, the Toyota gets another 40 miles of estimated driving range.

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Dulled by Weight

Turns out our K4 is heavier than both its predecessor and the Toyota bogey, which impacts virtually every aspect of the vehicle's performance, not just fuel economy. A 2019 Forte EX was the last 2.0-liter nonturbo version of the sedan tested by MotorTrend and it weighed just 2,885 pounds, 256 lighter than the K4.

Unsurprisingly, the K4’s acceleration is sluggish and, for some drivers, likely on the verge of being too slow: 0–60 mph in 9.1 seconds. The Corolla FX is quicker by a second (8.1 seconds), the Corolla XSE and old Forte by 0.9 second (8.2 seconds), and the K4 Turbo by a full 2.0 seconds (7.1 seconds). There’s no launch control, and whether in Normal or Sport drive mode, the routine is the same for the swiftest takeoffs: Rev to 2,100 rpm and let go of the brake.

Mass also takes a toll on turning. Whether turbo’d or not, every GT-Line comes with an independent rear suspension where lower K4 trims feature a torsion beam. The multilink arrangement helps with both normal and limit handling, but other systems—namely the K4’s transmission tuning and traction control—don’t like the car going too fast. Stability-control interventions in particular limited the K4's potential.

Like the turbo model, this K4 has responsive but artificial-feeling steering, and ride comfort should be acceptable for most shoppers. Some noise and harshness do transmit into the cabin, however, especially at high speeds and over certain stretches of compromised pavement.

A Better Binnacle?

Inside, the standard BMW-like curved display houses two 12.3-inch displays, a standard one for the driver and one for touchscreen infotainment. They look great; resolution is excellent, and the screens dwarf the 7.0-inch driver display and 10.5-inch touchscreen in the top Corolla. Our only complaint is that the backup camera is letterboxed and displays only in the center of the touchscreen, but its feed is tack-sharp at least.

The 5.5-inch touch-sensitive climate-control display between the two larger screens needs to move, though. It’s bisected by the squircle-shaped steering wheel, and when the driver’s right hand is on the wheel at 2 o’clock, the controls are completely obscured. Some redundant physical toggles on the center stack are helpful, but we’d rather be able to see the touchscreen. As it is, you have to peer around the steering wheel to see which controls to use.

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Generous Feature Set

This trim includes GT-Line styling, remote start, automatic headlights and high-beams, and a smart trunk (which means it will pop when you stand nearby for three seconds, but it isn’t fully powered). Wireless Apple CarPlay and Android Auto, a wireless phone charger, two front and two rear USB-C ports, heated front seats, and a power driver's seat are included, as well. And driver assists are plentiful.

Our test vehicle had the optional $1,100 Premium package. It brings faux-leather seat trim, ventilated front seats, a sound-absorbing windshield, and eight-speaker Harman Kardon premium audio. Our car also had the $900 sunroof package.

For as loaded as the K4 GT-Line comes, though, there’s not much going on behind the first row. The back-seat area has just USB ports and a small cubby at the back of the center console. The trunk has even fewer frills, with nary a cubby or elastic net in sight.

Regarding space for people and stuff, the K4 has much more rear legroom than the Corolla (38.0 inches vs. 34.8 inches) and greater cargo capacity (14.6 vs. 13.1). A K4 hatchback is coming, too, which should deliver even more useful space.

Verdict

The turbo version of the K4 was a 2025 Car of the Year finalist. With less power, though, the sedan is less compelling. It’s more efficient than the K4 Turbo, but some ergonomic missteps—including a low roofline that can make it harder to get in and out of—keep it from greatness.

Of course, the K4 GT-Line balances these demerits with sensational value. The as-tested price for our car was roughly $1,400 less than a similarly equipped Corolla XSE. That’s a not-insignificant amount of money for budget-conscious shoppers, and it’s even better when saving bucks gets you a modern car that looks good, offers decent cargo space, and is packed with modern tech and convenience features.

The regular K4 may not deliver the driving thrills of the Turbo—or the class-leading Civic—but it’s still a satisfying small car if you can handle life in the slow lane.