Kia K4 vs Subaru WRX: Specs Compared

Running cost over five years: at the EPA's 15,000-mile-a-year assumption the Kia K4 burns about $1,800 of fuel annually against $3,150 for the Subaru WRX. That $1,350 yearly gap compounds to roughly $6,750 over five years and $10,800 over eight — often more than the price difference between two trims of the same vehicle, and the single largest running-cost line item separating these two.

City and highway economy: the Kia K4 leads in both cycles — 30 mpg city and 40 mpg highway against 21 and 28 mpg — so its fuel-efficiency advantage holds whether you commute in traffic or cover long highway miles.

Powertrain choice: the Kia K4 is recorded with 3 distinct engine configurations (SIDI, 2.0, with DMS), the Subaru WRX with 2 (SIDI, 2.5). Across 8 recorded Kia K4 configurations and 32 for the Subaru WRX, the wider the engine spread the more the real-world fuel efficiency depends on which version you actually buy, so check the specific model year and drivetrain rather than the headline number.

Drivetrain and class: the Kia K4 is offered with Front-Wheel Drive, the Subaru WRX with All-Wheel Drive. All-wheel drive typically costs one to two mpg combined against the same vehicle in front- or rear-wheel drive, which is worth remembering when the gap between these two is small. The EPA classes them as Midsize Cars and Compact Cars respectively — the class drives the interior volume, cargo space and passenger space each one is measured against.

Tailpipe emissions: at their cleanest configurations the Kia K4 emits 264 g/mile of CO2 versus 374 g/mile for the Subaru WRX. Emissions track fuel consumption almost exactly, so the cleaner vehicle here is also the cheaper one to fuel.