No test pipes here ever. I went from stock cats w/ 3" B&B to a SZ turbo-back exhaust w/ high-flow cats. I couldn't stand the B&B drone.
Right now I've got it backwards: 2.5" SZ down pipes, 2.5" SZ high flow cats, 3" resonators with 3" dual round mufflers. All stainless 'cause I hate rust. I'll update the front sometime.