Ok with daylighers design the reason its such a large housing is because of the 150W daylighter is made that large for cooling the Sealed beam bulb. Now that being sayed the 150w lights are sealed beam light bulb, think back in the day with you moms old 70's LTD, you had to replace the whole headlight bulb reflector and everything. Same principle. Ok the 100W and 130W are H3 bulbs and you can just replace the bulbs. Now the 100w and 130w lights don’t get as warm as the 150w. Thus why the ABS plastic stone guards and clear guard melt under the heat. These lights aren’t as "big" as you may thing they will fit on any standard brush guard. The mounting bolt is fairly far back