I have two 10" Rockford Fosgate DVC subs.. Are these any good?? I also have a Pheonix Gold Amp and a Pheonix Gold Bass CUBE. I am looking for some changes to make the subs thump harder and louder. Any suggestions would be great! If there is something I could do to any existing components I have, please tell me! I dont know if I need to just throw my whole system away and start over-or tweak and replace a few pieces.. Also-what would be the best type of sub/amp to choose if I should do so?? Thanks a lot!!