Flowmaster introduces our American Thunder stainless steel cat-back exhaust system for the 2012-2021 Jeep Grand Cherokee with the 6.4-liter Hemi engine. This system uses Super 44 series mufflers and tuned resonators for an aggressive to moderate sound level and increased performance. Mandrel bent 3.00-inch 409 stainless steel tubing allows for maximum exhaust flow and durability. The system uses larger 4.00-inch polished stainless steel tips for a custom look. Max dyno gains of 6 hp and 9 lb-ft