Chuck - your speaker is still 8 ohms but voltage doubles making it 4x instead of 2x. If you think in terms of virtual ground that divides speaker into two 4 ohm pieces then you'll get 2x in each (same voltage, half impedance) but together it's 4x. Power supplies are not overdesigned 100% but you'll be able to handle peaks a little better. Damping factor will be twice worse (lower). It also might go over maximum current amp was designed to produce (minimum load).
I don't know if your amp can be bridged - some cannot be at all (already bridged) and others will require phase inverter for one of the amps.
I don't know if your amp can be bridged - some cannot be at all (already bridged) and others will require phase inverter for one of the amps.