I've read here that the GPR can stay on long after the idiot light goes off, does anyone see an issue with installing an LED to indicate when the GPR is on or off exactly?
All you need to do is get a radio shack "12v LED" (unless you like playing with resistor/LED calculators) and wire it onto the output side of your GP relay.
Red wire would go to the GP relay, black wire would go to ground. Done. Light will turn on or off in sync with your GP's, regardless of what the idiot light says.