Has anyone thought of upgrading their 825 watt system? Call me young at heart, but I like just a tad bit more thump in my commute. Not sure where to put the extra sub. Im thinking a 10" subwoofer in the back with a separate amp. This upgrade would cost ~$500 or so. Yeah, I know...there is already a sub implanted up front in the window. And would you trust a local Audio shop breaking open the dash and running new wires? That fear itself would cause me not to upgrade anything. Any other options?