Find a good bass head, 300-600 watts, and add a good 2x12 cab. If this is still not loud enough, add a 2nd identical 2x12. Brand is user preference, so go out and test some stuff and see what you like.Be sure you undertand impedance. If your amp is 4 ohms min, stick with 8 ohm cabs. If it's 2 ohms min, you have more options.