The front spoiler helps cool the engine compartment by causing a low pressure area behind it. At hiway speed the air passes thru the radiator and into the engine compartment. The low pressure area behind the air dam helps evacuate this heat down and to the rear. Having the air dam in place will cool your truck much better and you will hear the fan clutch much less as it will not engage as often. Less work for fan clutch will extend it's life too.
And, as said before - the air dam looks nice so I would certainly spend the money for it.
2012 F450 Ultimate Lariat pkg, 4X4, FX4, 5th wheel prep, camper pkg, 40console40 seat, Ingot Silver and Black guts
Reese Elite 18k 5th wheel
DuraFlap flaps all 4 corners
60 gal aux tank in bed
7.4 mpg as shown @ 70mph and 25740 lbs gross!!
2012 Fuzion FZ310 Monster Edition Toy Hauler 12,500 dry 16,500 loaded to play. 3100/3500 pin weight