I'm not sure I'd trust the spec's on your subwoofer, as far as power handling goes, but 3 ohms can be a tough load. Your amp delivers 225W @ 3 ohms to the sub at 10 percent distortion. Most spec's I've seen and trusted read like this for example: 225W continuous RMS power into 4 ohms, with 1 percent or less distortion. So the rated power of your combo at 225 watts includes significant distortion.
So here's what I recommend:
Using a multi-tester with ohm meter, check the DC resistance of your sub. Then call Parts Express (800-38-0531) with this information and ask if the following amp will run okay without running too hot at that load. Most 4 ohm amps are fine with a DCR of 3.xx ohms. This amp will deliver clean power and may be a great solution at that power level.
This is a good spec and it's for this amp. Rated power output (1% THD): 156 watts into 8 ohms, 233 watts into 4 ohms.