Should an amp have the same wattage as the cab? Or more or less? Obviously there are many threads on this topic but there are conflicting answers. Some say they have more powerful heads running into cabs with less watts, while others say this will damage your speakers. Which is true and why? Would it be safe for me to buy a 500 watt 4 ohm head to run into a 500 watt 8 ohm cabinet?