Spark plug wires: There are 3 manufacturers that I know of who make spark plug wires for the Supercharged 3.8. First is Koolwire, they are Grey in color and are the same diameter as the stock wires (7mm), and cost $39.99. And preliminary electrical test's show them to be 3 times better in every sense from the stock wires. Majorly due to the fact that they use Silicon Suppression wire instead of the stock carbon core wires. Second is Magnecor, they offer them in 8mm and 8.5mm sizes. Price is $56.94 for the blue 8mm and $93.09 for the red 8.5mm. These are 2 very different cables, one is not just a bit bigger. The 8mm is usually fine for a standard unmodified engine that's not raced, but if the engine is modified or raced (or driven hard), the 8.5mm is the way to go. There is also Jacob Electronics 8.5mm wires part number 4006669 - theses are for the black wires which cost an extra $15, otherwise they are blue. Magnecor product information and order information can be found at Koolwire can be found at most PEP BOYS.  Jacobs can be oredered from JEG's mail order. Expect 1-2HP out of the Koolwire 7mm wires. 2HP for the Magnecor 8mm wires and 2-3HP for the Magnecor 8.5mm wires.