Looking for an extra sub to replace an older free Polk sub that has died. Don't want to spend a lot but want really good MUSIC only performance. Don't we all want performance for the least amount of money. Saw this over at accessories for less. Any thoughts at the price point? I read some reviews and they were very good. BOSTON ACOUSTICSMSubwoofer 10" 500 Watt Powered Subwoofer Black NEW 399.00