Car amplifier powered by 360 power supply

[__DK__]

I have seen videos of people using an Xbox 360 power supply at home to power their car amplifier, which requires 12V.

However, my Xbox power supply has a 120W output, whereas my subwoofer is specified with a power range of 100-300 watts RMS (as stated on their website).

Will this be enough, or is there a risk of damaging anything, including the Xbox power supply?
What would be a way to ensure that the wattage is not exceeded?

Subwoofer: Infinity 1262w
Car Amplifier: Hifonics TXi 1200

 

[Arkless Electronics]

There IS a risk of damage yes and more likely a risk of protection circuits kicking in and sound cutting out.... maybe followed by it coming back on and this being repeated in cycles accompanied by loud bangs and pops. Just use a car battery. You could even use one with a trickle charger connected (depending on noise rejection of the amp) when the thing is in use.