That's a pretty broad statement that I will have to disagree with...
if your windows are dimming your lights, YOUR electrical system has some issues.
With that being said...OP, your amp(s) may be the culprit too, and the cap is doing nothing for you but that's another story.
Iam currently running well over 2000 watts from four class D amps in my truck and my lights do not dim at all. Iam registering atleast 14.5 volts at all times (including during big bass hits)
I have the factory battery and have done zero electrical mods to the truck.
Different class amps draw more or less power from your electrical system.
Your alternator may not be keeping up with the voltage needs (you can get that checked for free)
I guarantee that I don't have issues. Go try it on your dodge. I would bet my life yours will dim slightly too.