Also, grab a secondary cooling fan, as heat does terrible things to internal circutry, causing software glitches and whatnot.
Abosolutely do NOT do this. I bought one too when I first had an xbox and after a week I figured out the thing was doing bad and not good through personal testing and research. Besides the fact the fan's are annoyingly loud, there's a bunch of other issues with it. The fans don't actually svck heat out, but creates a vacuum inside the xbox, trapping heat inside. If it gets hot enough because of the trapped heat it can melt on your xbox which will void your warranty. It drains a lot of power too, but not sure if that's an issue or not.
The best way to keep your xbox vented propery is to set it vertically on a hard surface with atleast 3 inches of space on both sides and the back, more if you can manage.
On Topic: I've seen in VATS I might occasionally aim at an enemy, and when I start firing it teleports somewhere else, often times behind cover. However, for me it's extremely rare and could probably count the number of times it has happened on one hand (and thats with over 500 hours in the game).