You must match the output levels for the amps first otherwise the top or bottom will not sound balanced. Second is to get an active cross-over to be able to adjust the sound. I posted about this a few weeks back but have decided to stick with one amp for now. Too complicated with cables, power cords, room for all this stuff for the amount of time I am listening to music recently. If you can put in the time and expense, this is the way to go.
