I have 4 bolted directly to my bumper. It's really nice with 4 because I can use two for down the road and the two side lights for the ditches. I have a picture in my gallery that kind of shows them.

 

shoot Ive got 4 6" ebay cheapies (bigger than the 500s) behind my grill AND 4 hella 500s just below them on my custom bumper...no problems here, Ive had the lights behind my grill for quite some time now and want to switch em to hellas when i can.