8.5mm (didn't even know they make 8mm)

Why would you expect cooler running from good spark plug wires?

Honestly when I installed them I did a ton of other stuff to the car - so I can not say that the wires made the car run like a raped ape and gain 5 mpg....which it did. But it really wasn't just the wires. I don't think spark plug wires alone will buy you much unless the old ones are toast...and then even stock wires will help.

I like them because:
they last longer
they have better insulation so no stray voltage to ground
are easy to clean
well constructed
they possibly carry voltage better (less voltage drop)
and after 4.5 years of heavy turbo use they still give me the spark I need.


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http://www.fidalgo.net/~brook4/oilslubesfilters.html