I've read on here that you can reboot the computer system by touching the disconnected negative battery cable to the connected positve teminal for a second. Does this also work on other makes of cars?

 

Sure, it drains all the voltage out of the electrical system and forces the computers to default to the factory base. Sorta like rebooting a PC.

 

So, say in my 1996 Impala SS I can take the disconnected neg batt cable and touch it to the connected pos cable/term for 1 second and it zaps the computer to complete factory defaults????
What happens if that is done in a snazzy car liker my 97 XK8????

 

It's not exactly "zapping" anything. In fact, just disconnecting the battery will usually do the same thing. Touching the negative lead to the positive terminal is just to make sure there is no residual voltage lingering in a capacitor somewhere. And it doesn't reset things that are stored in non-volatile memory.