i am hoping I can put several in parallel to dropthe eff resistance to whatever the minimum the amp can handleA Bad, bad, bad, idea!
The general rule is NEVER connect outputs together. (That's why you use an audio mixer to mix audio signals.) Solid state amplifiers have very low internal source impedance (often less than one Ohm). The output of one amp "shorts out" the output of the other.
The most common "trick" is to make a bridge amplifier. That doubles your peak-to-peak output voltage (theoretically 26V P-P = 9V RMS) with a 13V power supply) and that gives you 4 times the power into the same load. Doubling the voltage doubles the current, so an 8-Ohm speaker "looks like" a 4-Ohm speaker to each amplifier. In theory you can get about 10W into 8 Ohms, but there is some voltage drop across the transistor/MOSFET and you can't actually get the full power supply voltage across the speaker.
High power automotive amplifiers have a voltage-boosting power supply.