Arctic Blue is made from Blue and Green (with a resistor on Green). And you can indeed rewire the whole thing to Guardian Blue with Silver FoC, You can even use the existing wires, but you need to remove the resistor first (cut the wire with the resistor in between the cutting points) and then extend the wire by using another piece of wire.
Obsidian V3 and V4 are absolutely able to handle that modification. No restrictions or limitations.
Does it have a BuckPuck or a Resistor setup (this resistor is not the one I mentioned above)? If it's Resistor, I recommend changing it to a BuckPuck when you upgrade to Premium Obsidian sound. Also, you need to change your battery setup to a 2x 14500 Li-Ion setup when adding Premium sound. LITE uses 4x AAA batteries which don't provide enough power for Premium sound.
The Obsidian premium V3 module I have is from a mystery saber and is powered by a resister setup with two 14500 Li-ion batteries. I just have to remove the guts of both sabers, swap out the battery pack and soundcard, then locate the appropriate wires and splice them together, right? Thank you so much for responding!