REMARK Catback Exhaust. Toyota GR Corolla. Elite Spec Quad Tip Stainless SteelQuad tip catback exhaust system for the GR Corolla. Same spec as our triple tip Elite Spec but now with 4" quad tips. We use larger diameter mandrel bent piping helps to reduce exhaust backpressure. The 3" piping and muffler canister are tucked up neatly under the car allowing ample ground clearance for those planning to lower the stance. The combination of the straight through resonator and high flow muffler canister give the exhaust a nice tone, and