Is Subaru working on a new halo STI sports car?

Subaru has filed a series of intriguing trademark applications that seemingly point to the emergence of a new two-door sports car and a corresponding STI performance halo – perfect timing seeing as we know Toyota is readying a new Celica for its GR portfolio.

Following on from Subaru Australia general manager Scott Lawrence’s February assurance that “STI is absolutely not dead”, the brand has applied to trademark the ‘Subaru ACX’ and ‘ACX STI’ nameplates with the local IP office.

The ACX nameplate dates back to 1985, specifically the Subaru ACX-II concept car that imagined a slinky two-door, all-wheel drive sports car packing a 2.7-litre flat six-cylinder engine.

While Subaru would be nuts to release an all-new six-cylinder sports car today, there’s certainly avenues and means for a new halo sports car to emerge and succeed in today’s emission-regulated market.

A modern ACX powered by a turbocharged four-cylinder heart could feasibly be cloned from the upcoming GR Celica given Subaru’s ongoing synergies with Toyota, the same ones that birthed both generations of BRZ/86, Solterra (bZ4X), Uncharted (C-HR+) and new Forester Strong Hybrid.

The revived Celica is tipped to pack more than 300kW from a new-generation 2.0-litre turbo-petrol engine – possibly with hybrid assistance – and drive all four wheels; the classic Subaru/STI combination (on paper).

But the Subaru-Toyota synergies aren’t enough on their own to confirm anything…

Toyota was spotted testing its next-gen World Rally Championship (WRC) car in February which just so happened to wear a coupe body, leading many to speculate the Celica was returning to its roots in a move that’d please purists for days.

Fast forward to April and Subaru debuted ‘Boxer Rally spec.Z’ – a turbocharged, all-wheel drive BRZ-based rally car developed for the 2026 All Japan Rally Championship.

Published outputs of the STI-fettled engine are 206kW/500Nm “or more” while a widebody kit provides more room for the completely-different-to-stock rally suspension.

Toyota previously offered Subaru a way back into the WRC as an engine and technical support supplier with reports pointing to a 2027 or 2028 return… 2027 just so happens to be when the WRC-spec Celica will debut, in line with the overhauled Rally1 regulations that’ll see the competition cars be far closer to the production versions.

Add all this together and it becomes apparent Subaru could be prepping to deliver a new performance halo – using Toyota DNA – to sit above the next-gen BRZ which has been widely speculated to morph into an EV.

Whether or not the hypothetical ACX STI would sit above the anticipated WRX STI in Subaru’s pecking order remains to be seen and could depend heavily on the terms and conditions set by Toyota.

Neither brand has confirmed the project at the time of writing, but other trademark filings by Subaru – including ‘Flat Shift’ and ‘Rev Sync’ – show the brand is seemingly committed to making a performance comeback, potentially even with manual transmissions in mind.

Join the conversation at our Facebook page
Or email us at editor@carsales.com.au