Image Credit: Subaru.Subaru may be preparing something interesting for performance-car fans, as the Japanese automaker has filed trademarks for four new names this year: ACX, VPX, ACX STI, and VPX STI.The filings immediately sparked speculation among enthusiasts because Subaru has not introduced an entirely new performance-oriented nameplate in years. Outside of its growing EV lineup, the company’s range has remained relatively familiar, centered around models like the WRX, BRZ, Crosstrek, and Outback.What makes the new trademarks especially interesting is the inclusion of the STI badge. Subaru Tecnica International has historically been reserved for the brand’s highest-performance vehicles, most famously the WRX STI, which became a rally icon around the world.AdvertisementAdvertisementNow, fans are trying to figure out exactly what ACX STI and VPX STI could eventually become. Subaru has not officially commented on the filings, leaving plenty of room for theories and speculation.The STI Badge Still Carries WeightEven though Subaru discontinued the gasoline-powered WRX STI several years ago, the STI name still holds enormous significance among enthusiasts. It represents some of the brand’s most beloved performance cars, particularly during Subaru’s dominant rally years.That is why the trademark filings are important. Subaru could have simply registered ACX and VPX as ordinary future model names, but attaching the STI suffix strongly hints at sporty or performance-focused intentions.The company has also repeatedly said it is not abandoning enthusiast vehicles entirely, even as the industry progresses toward electrification.AdvertisementAdvertisementSubaru executives previously hinted that future STI models could potentially combine electrified technology with traditional performance characteristics. Whether that eventually means hybrid power, EV performance, or something entirely different remains unclear.ACX May Have Historic Subaru RootsImage Credit: Subaru.Interestingly, the ACX name is not completely new to Subaru, as they previously used the ACX-II name for a futuristic concept shown at the 1985 Tokyo Motor Show.That concept eventually evolved into the Subaru XT and later helped inspire the SVX coupe. In Japan, those vehicles were sold under the Alcyone nameplate, fueling speculations that ACX could stand for something like “Alcyone Coupe eXperimental.”Subaru has also hinted at sporty coupe ideas in recent years. At the 2023 Japan Mobility Show, the company unveiled the Sport Mobility Concept, a sleek electric coupe larger than the BRZ that suggested Subaru may still be exploring additional enthusiast-focused models.AdvertisementAdvertisementLaunching another coupe in today’s SUV-dominated market would certainly be risky. However, several automakers have recently shown renewed interest in niche enthusiast vehicles despite crossover sales continuing to dominate globally.VPX Remains A Complete MysteryWhile ACX might carry some historical context, VPX is much harder to decode. Subaru enthusiasts online have already begun dissecting the letters, but so far, there is no clear explanation for what the name could represent.Some speculate the “X” could once again stand for “eXperimental,” similar to the WRX name, which famously stands for World Rally eXperimental. Beyond that, however, the remaining letters remain entirely speculative.The name could reference a future technology platform, an electrified performance system, or perhaps an entirely new vehicle category for Subaru. The company’s motorsport activities currently span rally racing, endurance competition, and GT racing in Japan, so there are several possible directions Subaru could take.AdvertisementAdvertisementOf course, trademark filings do not always guarantee production vehicles. Automakers often register names simply to protect future branding opportunities, even if the projects never move beyond internal discussions.Subaru Still Seems Interested In Performance CarsImage Credit: SubaruEven if these trademarks never become production models, the filings suggest Subaru is still actively thinking about enthusiast-oriented products. That alone is encouraging news for fans worried the company may fully abandon performance cars during the transition toward EVs.Subaru’s enthusiast reputation was built largely on rally-bred machines like the WRX STI, and the brand understands that heritage is important. The continued use of the STI name indicates Subaru likely wants to preserve that identity moving forward.The challenge will be balancing enthusiast expectations with emissions regulations and changing consumer preferences. Performance cars remain a shrinking niche, while crossovers and electrified vehicles continue dominating global sales.AdvertisementAdvertisementStill, Subaru has never completely followed the crowd. Whether ACX STI and VPX STI become electric coupes, hybrid performance sedans, or something nobody expects, the mystery alone has already succeeded in getting enthusiasts talking again.If you want more stories like this, follow Guessing Headlights on Yahoo so you don’t miss what’s coming next.