2006 Ford F350 Ram Air or Cold Air Intake

You mean the difference between ram and cold air? Ram air intakes only use forced air from the front of vehicle to help bring in cooler air into intake. Cold air intakes actually have a cold box that produces cool air, similar to A/C, that is then sucked up into intake. True cold air intakes are usually much more expensive then the ram air intakes and are much more effective as well. When you gain HP your likely to lose fuel mileage though. Although intake upgrades will only gain 2 or 3HP at best, despite what the companies claim.