Or is there something I'm overlooking? The reason I ask is that 200ohms is not a standard resistor value (so I don't have any in my parts box), so it doesn't seem likely that Tracy would chose that value for a simple voltage divider, unless there is another reason.

S. Todd Bartrim 
 

Tracy said 200, and I didn't question it.  I believe I used two 100 ohm resistors instead, and they were typical Radio Scrap items.  I believe Tracy said he got the resistors online somewhere, and used 1% tolerance.   

Looking at the circuit, I wouldn't use anything significantly different from 200 ohms, because one of those resistors is in parallel with the resistance of the sensor.  I would suspect this would just become a calibration issue though.  My temps have seemed correct with the new software, though I'm hoping I can make the oil temp prove to be too high so my oil temp issues will go away :-)

Rusty