My car has not been down on power for awhile. I have been burning the number #5 plug wire quite often and go back to Napa every couple of months to swap out my old for new set at no charge. Tonight I popped the hood with the car running and what a light show! It appears that all the wires are letting sparks get past the boot area and my coil is also shooting sparks. (anyone know how much a new one cost?) What plug wire do you recommend? Right now my 7mm Napa aren't cutting it.