dont mix subs ..they are different and react different and if not the same ohmage...... the higher impedance sub will rule......and if they react different then you will have phase shifts out the yin yang............... 3 dvc 6 ohm coils will give you 4 or 1 ohm........... but 2 ohms is hard to get with what you want to do....4 subs would work though wire 2 4 ohm vc dvc's in par.....then each pair of parralle wired subs.wire them in series with the other pair......