Spark plugs as sensors(thinking out loud)

[talltom]

The way I understand this is exactly what the 
SAAAAAAAAAAAAAAAAABBBBBBBBBB(booHoo) story is from 93 up with 
their trionic system, which is largely software configured. The
theory is that they either measure resistence at some point during
the compression stroke or spark and log the voltage required  and 
use the values derived to compute charge density and temperature and 
adjust timing on a per cylinder basis.  These things were turboed too.
   Really don't know much as they are pretty closed mouth about whatever 
they've done.