MXP Dual Single Tip Cat-Back Exhaust | 2015-2020 Subaru WRX/STI (MXCRVAS)2015 2020 Subaru WRX STI Dual Single Cat Back Exhaust System by 2015 2020 Subaru WRX STI Your 2015 2020 Subaru WRX or STI may be a powerful street and track machine off the showroom floor, but the factory cat back sure doesnt let you or your competition know it. MXP's Dual Single Tip Cat Back exhaust for 2015 2020 WRX and STIs adds a brutal, aggressive exhaust note to your wicked Subaru build that is sure to turn some heads on the street, autocross