The long and short of it is this.
You're not gonna believe us and want to argue that it's got to be worth it because you saw it on TV.
It won't do a darn thing for you to put dimples on your car/truck.
I started up here in Ecomodder 3 years ago with this exact idea "Magnetic Stick-on Dimples" and have since learned a huge amount regarding aerodynamics.
Read this for starters. There's a statement about dimples in there for you.
HotRod Mag Aero Article
Search the site for A LOT of info.
My part in this discussion is over.