9.3mm spark plug wires

Has anyone ever used any those after market spark plug wires that are 9.3mm. is that too thick for a 97 civic and could it decrease gas mileage?

i dont think it should harm the gas milage but it would make a difference power wise tho. but 8.5mm should be good enough unless u plan on goin with force induction. you should also consider a MSD ignition if u want to get the most out of those wires too