*Fire Control, target Sebbish. Warm up the beam. And... FIRE!*
Exits are to the sides and rear. Personal flamethrowers are located beneath your seat in case of emergency or naughty disposition. If you run into any Shivans while crawling through the ductwork, it's probably just Carl. Give him your lunch, don't make any sudden moves, and you'll be fine.
Anyway, as for your questions: 1) I dunno, never tried it, or heard of anyone else trying it. Backing up your registry before making changes is always a good idea. 2) Under the place where it says Hard Light Productions Forums
in the top right of the screen there is a search function. Use it to find a thread that talks about the high-res texture registry hack.