I'll be running 2 coolant temp sensors (one for gauge and one for megasquirt). I just bought the sensors that the megasquirt is calibrated for (coolant temp and Intake temp). DIYautotune.com. under $20 each.
I read a good bit of that knock article. Very cool! I had read something else at one point that was much more confusing, and seemed a bit more complicated (might have used our factory sensors).