I don't know model numbers, is that ppi a 2 or 4 channel? if its a 4 channel bridge 2 and run a cross over, or its built in one, for the sub, bass is normally mono anyway, then run the other 2 channels for the doors. you need more power for your bass than your mids and highs, if your not trying to pump bass out of a 6" speaker it will sound better and last longer. its always better to have more pwer than not enough.