I have a 2013 MKZ w/ the THX sound system. I have a pair of 12 inch Kickers in a box sitting in my closet. Should I run power to an amp and install the extra subwoofers? Will I have to remove the factory subwoofers? Will it throw the whole system into chaos? Will the world end? Or will I just merely relieve my 1999 days of bumping around town?