3in from headers back. single exit. the reason you dont want a dual is because of flow, more bends and more pipes for the gas to go through equals less torque....UNLESS you have true dual and no ypipe.
My truck is still a work in progress and i was cheap like you and all i have at the moment is intake, gibson shorty headers and i took off the exhaust after the first resonator. Now I love the sound BUT im running rich and my frame before the axle is BLACK! lol I will be purchasing a magnaflow y-pipe and 3in single exit cbe come the new year