need a voltage regulator

I am a little lost here as this is out of the realm of what I am usually work on. I have a GM vehicle and I purchased a Dashtronix unit.   Essentially its a set of digital gauges that display on the dash. Anyway, it unit and accessories require 5.0volts. My vehicle of course runs on 12v. Where can I find something to regulate the voltage so the input voltage is dropped down to 5v. I can't use a resistor because I need accurate 5v all the time. Not variable based on alternator speed. Thanks, Dan1971 Chevelle SS

1989 Corvette

1996 Impala SS

I would say the simplest route is to go buy a hardwire kit for xm satellite radio. They run off of 12v and output 5v. Or you could find a 12v cig plug adapter that outputs 5v and chop it up for your needs. This way you aren't reinventing the wheel, you are using an already tested design.