WiLL, be careful!! Not all amplifiers bridge in the same manner!! Always check the manual first before you go plugging in wires.

Bridging an amplifer will not produce more power, it just produces it "differently" Lowering the impedance however can increase power, but only to a certain point. Everything in car audio is a tradeoff - as you decrease inpedance, you do increase power (generally - depending on the amp) but you also decrease stability.

That amp is probably good for a 4 ohm mono load, so I would leave it as is.