92Efi4.9

I have a 92 f150 efi 4.9 with a stopped up catalytic converter and broken air pipe. I'm thinking of designing my own exhaust. I'll start by cutting the two pipes in front of the converter leaving the o2 to manifold alone, and connect a 2" dual in/out converter(with air) then two 2" pipes to a dual in/out muffler then two 2" tail pipes side by side exiting behind rear passenger tire. Does this setup sound like it'll boost performance? I'll actually be cheaper than stock