OK im going to buy some Fi sub's..im thinking abut getting 1 BTL 18" with P Chamfer, Cooling, HiXmCoil, Daily and I Heat Ring...or 2 SSD 18"s with FlatwindCoil and CopperCoil upgrad's...both combo's will be used up to spec like Rms watt's , Ported box cuft, Hz and so on...iv never heard these sub's in person so im not sheer whats better or i should say whats louder or hits harder...what ever you want yo call it...Thanks billy!!!