hey im thinking about buying a head unit for my system but im not sure about what spec it needs to be :/ ok so im installing: 2 edge 12inch subs hooked up to a 1800w max 600w rms amp i think its mono block. and 1 4 channel fusion reactor 1000w max amp linked to 2 fusion 6x9s and two fusion 5&1/4inch speakers. i need some help on the head unit required thanks