aFe MACHForce XP Exhaust Cat-Back 2in SS-304 Cat-Back Exhaust for 05-08 Porsche Boxster S (987.1) H6aFe MACHForce XP Exhaust Cat Back 2in SS 304 Cat Back Exhaust for 05 08 Porsche Boxster S (987. 1) H6 aFe is proud to introduce the aFe ELITE cat back exhaust system for the 2005 2012 Porsche Boxster S (987. 1 & 987. 2) with H6 3. 4L engine that uses the OE tip. In recent testing with the OE tip, this exhaust system resulted in a max gain of 22 horsepower and 30 lbs. x ft. of torque. aFe spent countless hours of R& D to develop the perfect balance of