During break in, woven fibers that comprise the spider begin to stretch out while the surround becomes more pliant.
After they’re broken in, you’ll be able to play lower, with a greater dynamic range, and with better efficiency than before break-in.
Your stock electrical charging system was designed and built for the stock features of your car.
Whether you need a second battery for car audio is determined by your application and by how much power your amplifiers are using.
Relying on a stock electrical system for the massive amperage that car audio amplifiers require, while still supplying your vehicle with the current it needs will result in low voltage and other problems.
High Output Alternators increase the amperage of your system.