RawbDidIt
I'm Awesome
amp will be placed under the rear seat. haven't decided on driver/passenger side yet, though.
Run whatever wire you have handy to your mounting position, then measure that. I usually use a spool of speaker wire, because I always have that handy, but if that doesn't work, try rope, or even yarn. You don't have to bury it the way you would the cable, but make your best approximation and add a couple feet, you'll need that extra couple feet when you run your ground anyway (just wrap the ground black so you know it isn't live).