Subaru has recently filed trademarks for 'ACX' and 'ACX STI' in Australia, leading to various speculations about the potential new models. The ACX name harkens back to the ACX-II concept car from the 1985 Tokyo Motor Show, which was a two-door vehicle featuring a 2.7-liter flat-six engine and all-wheel drive. Enthusiasts speculate that the ACX could be a sporty 2+2 coupe, similar to the Honda Prelude, while the ACX STI might signify the return of the STI badge in a production model for the first time since the WRX STI was phased out in 2021. Another possibility is that the ACX could be a rebadged version of the upcoming Toyota Celica, which is confirmed to return with a hybrid powertrain and all-wheel drive capabilities. This collaboration could continue the longstanding relationship between Toyota and Subaru. Design-wise, the ACX might take inspiration from Subaru's 2023 Sport Mobility Concept, which combines a two-door layout with rugged SUV aesthetics. However, until more information is released, these ideas remain speculative.