Moose10,
I have heard of alot of people doing that and there were no problems. Your IAT runs on current. In effect a pyro prob kind of makes it's own current and the wiring associated with it must be a certain length to match the pyro internal elements.

 

No, it's a variable resistor, not a thermocouple. Extending the harness will not cause any problems. The only "problem" you might experience is that the grid heaters run more than they used to due to the IAT not getting warmed by the engine heat.