Hi all. I'm going to replace my exhaust and planning on going to 2" with a high flow muffler such as flowmaster. Does anyone know if I omit the cat in that scenario if that will be too much of a drop in back pressure? If I omit the cat should I stay with stock 1 3/4"? I'm looking to increase top end for highway speed and fuel economy but don't want too much of a sacrifice at bottom end either. (84 22r carbed pu)