Here's my Firecore story ; i have a set of the 8.5mm pro-fit wires on my car earlier this year and started to notice a slight miss at high rpm. Upon closer inspection i found one wire (#2) laying right across the header tube. Pulled it back and it was burned right to the core....all insulation was GONE ! That explained the high rpm miss !
Taped it up, rerouted the wire and all was well again....miss was gone & the plug cleaned right up.
I measured the resistance and it was still 104 ohms...amazing.
At Norwalk i showed Rick the wire and he replaced it for me...no charge.
Ron