Monster Exhaust System Single Exit Turndown 87-01 Jeep 4.0L Cherokee XJ Banks PowerHuge 2. 5 inch stainless mandrel bent tailpipe. Straight thru Monster muffler flows up to 108 percent better than stock. Slashes backpressure. Throaty sound. Constructed of heavy gauge stainless steel, Banks Monster features a supersized, 2. 5 inch tailpipe. Banks Monster muffler, its straight through performance muffler, is the industry's least restrictive. In comparison tests, Banks muffler flowed 543. 2 cfm at 1 psi a 108 percent improvement over