in my opinion, caps are sorda pointless. what happens when you have a long period of bass beats? The cap cant store enough energy for a 1min solo... Its only good for the first few beats.
Not even that.. How can you add something that runs off the electrical system and expect it to IMPROVE the system. If it were possible to "create" energy in this way, why haven't we got our houses running off caps? Also, caps WILL cause voltage drop. I've seen them cost as much as 1.4v!!!! It's usually around .3-.5v, though.