The best interior upgrades for the 2015-2021 Subaru STI are carbon fiber steering wheels, weighted shift knobs, modern head units with wireless CarPlay and Android Auto, and carbon fiber trim pieces. These parts sharpen the cabin's look and the feel of every shift without touching engine performance. When in doubt about fitment, check your year and model before ordering.
The STI's cockpit is where its driver-focused character lives, and this collection is built around it. Carbon fiber steering wheels — including JDMuscle's Carbon Lite and custom series for 15-21 WRX/STI — put motorsport style in your hands, while Tanso carbon fiber shift knobs, leather and suede options, and carbon mirror and dash trim complete the theme. Head unit upgrades add wireless Apple CarPlay, Android Auto, and backup camera support that the factory stereo lacks.
Popular brands here include JDMuscle, whose Tanso carbon fiber line covers steering wheels, shift knobs, mirror covers, and dash trim, plus Morimoto lighting upgrades. Shop related cabins too: 2015-2021 STI interior parts, 2015-2021 WRX interior parts, and the full interior collection.
Standout picks: the JDMuscle Carbon Lite carbon fiber steering wheel for 15-21 WRX/STI and the JDMuscle Tanso carbon fiber shift knob. Learn why so many cabin upgrades use it in why carbon fiber parts are the best option.
What shift knob thread pitch does my STI use?
Subaru manual shift knobs commonly use M12x1.25 threading. Match the knob to your transmission — manual knobs do not fit automatic shifters.
Will a carbon steering wheel keep my factory controls?
JDMuscle carbon wheels for 15-21 WRX/STI are built around the factory hub pattern and retain the stock airbag and steering wheel controls. Confirm the exact application in the fitment notes.
Do interior upgrades require a tune?
No. Interior upgrades — steering wheels, shift knobs, head units, trim — do not affect engine management, so no tune is required.
How hard is a head unit swap?
Most modern head units are plug-and-play with a vehicle-specific harness and take an afternoon. Carbon fiber trim pieces are typically adhesive or clip-in.
