Jurisdiction / State: North Carolina

I recv'd a speeding ticket for 70 in a 55 zone. I have recv'd no citations in the prior 3 years. I have learned about making the plea of "improper equipment" and have learned to have an attorney represent me will run approx $225.00. My question is, if I rep myself what are my chances of success, making the same plea? Also, is this as simple as showing up, stating my plea intention and walking out w/ a reduced charge or am I going to have to actually argue the case/show evidence to convince a judge to reduce the charge?