Explanation of the issue posted by qg_626:
"There is some speculation, and apparently some testing by APS has confirmed this as well....that there is some kind of interference or anamoly with our crank angle sensor wire. Essentially, there is some noise in the signal that goes to the ECU, and under certain circumstances, this can generate a false or muddy crank angle input to the ECU. Obvisouly, if this happens, there is a chance that the coils may fire before the pistons are at TDC, and could contribute to detonation/preignition. Peter has also described this as "scattered ignition timing". It is something that occurs only under certain conditions, and only on certain cars. Some cars exhibit no anomolies...others do.
But APS felt it was important enough to include a new shielded crank angle sensor wire in their kit. You can see this on their website.
So...just to be safe, it would be HIGHLY ADVISIBLE for everyone with the Greddy and PE kits to immediately swap their unshielded crank angle sensor wire with a new shield wire. I would hate to see these new forged motors start blowing up due to this potential problem."