I currently have 2 15" type r 1542d subwoofers, they are the dual 4 ohm version and i am going to bridge them down to 1 ohm, in a open enclosure in the back of an expedition. I am getting a new amplifier and i am having a hard time selecting a new one. I have narrowed my choices down to either the PIONEER PRS-D2000SPL or Rockford Fosgate Power T20001bd amps. Please help me make the decision and provide info as to why i should choose the amp. I am planning to upgrade my woofer in the next few months, i will be purchasing a single 18" Fi BTL fully loaded, so please keep that in mind. Thanks in advance for everyone's help and input.