1995 Chevy Monte Carlo remote start

Do you mean that I cut one VATS wire, hook the white to the key side, the orange to the computer side, and just remove some insulation on the other VATS wire and hook the gray to it? And does it matter which one?

why dont you just grab a relay and a 20k ohm resistor, or a series/parallel combo of 20k ohm?

you dont really need the relay if youre ok with doing it that way.  just cut the two VATS wires and solder the resistor in between the two decoder side wires.  the relay leaves VATS in tact, soldering the resistor disables it.

Use 3 resistors in serial connection. 4.7K, 470 and 47 ohms. This will give you in theory 5217 ohms. Since you have a 5% tolerance in the values, you can play with different resistances to get the exact value using a good DMM to read the total.