I'm with dotster, where your power supply having heating issues would have nothing to do with your game freezing. The game disc, however, could... but since others said they had the same problem, i highly doubt that that's the problem.
It's probably just an issue of the game being poorly written, causing it to lock up for seemingly no reason.
ANYWAYS, back on topic. I really see the faceplate thing to be really stupid. It's not going to impress your friends, because there's no creativity at all. And, it'd be easy to have the same colors as your friends, which in my book ranks as uncool. I love my heavily case modded original xbox's (2 of them) that I did with my own two hands and they look awesome, and drop jaws wherever i take the machines.
So I guess Im saying I'd rather paint, cut, and light up an xbox 360 myself instead of buying a stupid faceplate/case for it. Just my two cents, y'all.
-Dan