Anyone know of where to get a deal on a full set of 8 glow plugs and the module? After some research I think I want to stay w/ Motorcraft plugs. And I've seen several places selling what they call a "relay module" and the picture (labeled "generic") shows a plain round relay- in my understanding, the truck has EITHER a module (rectangular box) OR round relay (which mine would be the first). Seen em priced from $50-180: kind of a range there, so wondering if anyone's had to purchase before and where u went? Thanks!!