hmmmm, don't know too much about this.. But i'd say to find the size of the power cable, i would find the power ratings of each neon, add them up and then you should buy a powercable capable of handling that power - too small a cable, will make heat, heat will most likely burn out your wires and set your car on fire :P Also, don't forget to put a fuse on this power cable, you don't want a short circuit somewhere that can't be stopped... Running of power cable - make a neat path through your engine bay with the cable, zip tying it to places or whatnot.. Then you'll have to find a grommet(?) in the firewall to go through, you will see blank ones and also ones with cables going through them.. I have no idea how to put it through with the other cables correctly, probably good for someone else to tell you that. Just make sure the cable isn't going through a hole where there is no rubber around it, the metal edge could wear through the cable causing a short.. And yeah, good luck with your neons! Hopefully someone else here can clarify - looking at you d-ice :)