I doubt they check for an exact value. I will certainly try higher values when I get around to making the mod as they should mean less heat is produced by the resistor.I think somewhere along the way someone figured out that the "correct" resistor is a 4 ohm one. But, it seems that 8 ohm resistors work too. FYI. I used a 4 ohm, 10W one, and it works great.