I know a lot of guys already added them, but added a Federal Signal MPS302U-R. Perfect fit where the rear reflector( pretty much the exact dimentions ) is over the plate and mounts flush( well not flush it is a surface mount and it is only 0.43in thick ) and had to drill 3 holes vs. dremeling out to make the whelen fit flush...Tried to load a video can't seem to figure that one out. I don't have picture only video I will take a couple pictures tomorrow and add them then