About three years ago I put together a system on a tight budget. I found this box with two 12 inch Cerwin Vega subwoofers for cheap off Craigslist. The box is HEAVY, and measures 34x17x13. I'm running a JBL 7001 700 watt amp. I've never been happy with the sound and I'm looking to upgrade. Would it make more sense to just upgrade the subs and use the current box? Or replace the box and subs? Anyone recognize this box and know if it's decent quality?