Aside form the upgraded STi package, the S04 sports a more power thanks to new larger, ball-bearing turbocharger from FHI. The added bits offer 320 bhp and 319 lb-ft of torque from the small two liter engine! The performance parts include a large-sized twin scroll ball-bearing turbo, sports ECU, sports catalyzer, titanium sports muffler, silicon air intake duct, air cooled engine oil cooler, high strength casting pistons, STI large size intercooler, hard type engine mounts and balanced engine internals.

The chassis was completely reworked with a new suspension featuring lower springs, performance dampers jointly developed by YAMAHA and STi, piro-boll bush suspension bushings, 21mm roll bars, sports brake pads, 18x8.5 BBS alloy wheels, strut braces,

Inside the S04 gets a leather wrapped SRS steering wheel with STi stitch, shift knob with stitch, an aluminum shift boot ring with S204 serial number, sports pedals with aluminum pads, full auto air conditioning and exclusive bucket seats that recline. Outside, customers can choose three colors: WRC blue, grey or black with standard options being HID headlights, electric mirrors, exclusive front skirt, silver mesh front grille, Rear wing spoiler with high mounted stop lamp, Aluminum front hood, Front corner spoilers and a rear diffuser.