Diamond Audio D6,Cerwin Vega Stroker,Memphis Mojo?

3 12's would be loud , the mojos are some good subs . your systems going to be all in the box as far as results , dont go cheap with the box . Ideal tuning is your personal preference , the lower you tune it the deeper its going to sound but it wont have as many db's on the meter. Most people go around 45 hertz to 40 hz . Do some researching and checkout some termlab vids on youtube with the subs you have listed .