Because watts aren't watts. They lie. The car audio market is not regulated, so they can claim whatever off the wall number they want. General rule of thumb is you get what you pay for. Top dollar amps generally are true to their claims, use quality parts, and hold solid warrantys....none of which can be said for a no name manufacturer. Take a look at the fuse next time you see a 4000w amp for $125, I'm willing to bet it will be about the same size as that of a name brand 200w amp.