I've always been jealous that my 2006 Impala SS doesn't have the windshield display that some of my colleagues have.  I've tried a variety of different alternatives to allow me to keep my eyes on the road but still see my vehicle speed, RPMs, etc..  Before this product, the closest I came was with an app for my Droid that used the GPS to determine how fast I was going.  The downside to the GPS-based solution was that there was often a delay between speed changes, the speed displayed wasn't always accurate, and because of where I live, I don't often get a good (or any) GPS signal to work with.

This solution is excitingly better.  Instead of being at the mercy of whatever GPS signal my cell phone could pick up, this unit by ADD plugs into my OBDII port and reads data directly from the car itself.  The HUD is exactly as accurate as the gauges in my dashboard and it works no matter where I am, including in tunnels, on highway in the middle of nowhere, or between tall buildings.  Moreover, installation is a breeze and, once done, it always available.