HT Autos is a UK based company which makes the most popular body brand name body kit for the 2015 WRX / STI. They have continued their development on the vehicle with an artfully crafted fender flare / wide arch kit. The kit comes in raw urethane and is intended for a body shop to install and paint.
These flares will allow you to run up to 55mm per side over stock size. They also give your vehicle an impressive look
This kit will give you many options to run wider wheel / tire setups.