1998 Honda Civic EX Sedan 5-Speed
Viper 5002 alarm system

I'm going to place the alarm under the front drivers seat, and will run the powers wire(s) to a constant 12V in the under-dash fuse panel.

Question:
Do I run each individual power wires to the 12V source?
Do I turn all power wires into a single wire, close to the brain, and run that? If so, what gauge should that wire be?

Thanks again in advance!!
-Joseph