1. Voltage Drop - You probably don't have the power/wiring to support the amp. Check the voltage drop on a burp/tone. If it goes less than 11.5, the amp will get hotter when producing the same power.
2. You said *** twice... and one was *** package... I'm waiting for that UPS box. //content.invisioncic.com/y282845/emoticons/veryhappy.gif.fec4fed33b4a1279cf10bdd45a039dae.gif
3. Low Impedance - The w7 shouldn't kill the amp, unless you're running the 13w7 - dual 1.5 ohm coils, in parallel. Then you're impedance is 0.75, so wire in series. Check your DC resistance using a volt meter across the speaker terminals.
@Fique: Lower impedance causes the amp to run less efficiently, and produce more power. This combination creates alot more heat. Class D amps can produce about 85 - 88% eff @ 4 ohm, but will be 70 - 75% eff @ 1 ohm... while outputting more than twice the power. According to rough calculations, that is 4 to 6 times the heat generated.