lets say i have a custom 2 1/2 in piping from the cat and i want to remove the cat for a louder sound, will it cause that pissed off bumble bee sound(RASP) also how will that effect my air/fuel ratio guage for my nitrous?

99 atx SE 75shot NX ngk plugs taylor wires injen intake superchip custom cat-back tsudo exhaust ground control coilovers kyb struts 18in RH-C5 svt bumper