Subaru has been spotted testing a prototype of its WRX sport sedan fitted with some performance upgrades, suggesting a hotter variant is in the works.

The wheels are bigger than the standard 17-inch set found on the WRX, and they house a Brembo brake package with red calipers and cross-drilled rotors that almost reach the inner lining of the wheel rim. There's also a small spoiler attached to the trunk lid.

The prototype isn't for a WRX STI, as Subaru has ruled out that option, at least for this generation of its compact performance sedan. However, we could be looking a new tS variant.

The designation, which stands for “tuned by STI,” has been used on past WRX generations sold outside the U.S. The cars feature upgrades developed by STI but are tamer than dedicated performance models developed by Subaru's in-house tuner, although there are also some WRX STI tS models as well.

2024 Subaru WRX hotter variant spy shots - Photo credit: Baldauf

Upgrades found on tS models can range from mild to wild. They include items like oil coolers and aero parts right up to adjustable suspension and engine tunes. The WRX at present is powered by a turbocharged 2.4-liter flat-4 delivering a peak 271 hp and 258 lb-ft of torque. It can be had with either a 6-speed manual or CVT.

While Subaru has previously offered a BRZ tS in the U.S., none of the previous WRX tS variants have been sold here. However, the car in our spy shots is likely being developed with the U.S. market in mind, as it was spotted testing on local soil and wearing Michigan manufacturer license plates.

Given the minimal camouflage gear on the prototype, a market arrival is likely close, possibly as early as the 2024 model year.