I have an 18" IA Death Penalty and a Kenwood hu. I am wondering what amps you would recommend for the 18" I also have Kicker KS series speakers amplified on a hifonics zues. basically wondering what amp to get and if facing the subwoofer up or facing it toward the front seats would be better..if I face it up would it be a big noticeable difference. I plan to tune it around 37hz