If you find your system doesn’t seem to strain your current electrical system, is it worth upgrading?
The power wire off of the alt these days are usually somewhere in the 4 Guage territory. I find the most important is just upgrading the ground. For some reason most manufacturers are running a 8 or 10 Guage ground from the engine to body. Alot of charging/starting issues I find when diagnosing are usually ground wire related.
I’m sure you know that less voltage drop means less amperage drawn usually.
Also note that the big 3 upgrade is never really needed with trunk mount battery cars. They tend to have a run of 0 gauge front to back. Overkill for any system sub 2000w rms.
I always found that the better ground you can get, the better. I usually found a good seat mounting bolt and sanded off the paint and primer under it to run the ground. Always went 1 larger gauge size than needed running to the battery. Never had to change or upgrade a alternator or battery. If i ever seen any dimming i would add a larger capacitor in the line. I have always noticed slight benefits to the sub sound with a capacitor so its mandatory for any system I do now.
Also, a circuit breaker is worth it instead of a inline fuse.