some people have just grounded the black wire to the frame and splices the red wire into the hot wire on the parking lights or fog lights...
me personally, i used a seperate switch so i could turn them on or off at will (like when the headlights are on, you cannot see them, so i turn them off. and night time car gatherings i can turn on ONLY the angel eyes with no other lighting...)
to do this you will need a switch, and inline fuse, and extra wire... if you want to do this lemme know and i will try and explain what i did