for the headlights i mounted them on the front side of the core support right behind and below the headlight with some strong 3m double side tape and been on there for a couple months without problems, just clean the area real good before applying the tape. the fog light ones are on the bracket just to the inside of headlights kind of by the horns.
You will want to mount them somewhere in front of the radiator. Some of the ballasts can create a magnetic field which can interfere with your radio. I had this problem on my tacoma. I moved those damned things at least 5 times before I found a spot that would block them....yes, in front of the radiator.