#1 it uses 4x40 fuses dont use different fuses in the amp... it will go pouff.

#2 if you want to run mono you have -+-+ use the first - and the last + but make sure your sub is wired to one ohm first then put your negative to that first - and your positive to that last +.

#3 In lamens terms, the lower number will lower the ouput of your amp and the higher number will increase your amps output. With the turn of a button, think of it as a bass boost.