Supreme suspension lift/level kits

[mchnhd4]

Just bought a 2.5" front and 2" rear lift kit by supreme suspensions. On the site I bought it (American Trucks) it doesn't say anything about a differential drop kit or needing one. On supreme's site, they offer the lift kit with the differential drop kit, and also without the drop kit. The lift kit without the differential drop kit says 2.5"+ 4WD MODELS MAY REQUIRE A DIFFERENTIAL DROP KIT(A1987). Soooooooo do I need this kit or not? I suppose it's better to align the differential as close to the original design as possible to avoid premature wear or if Im going to be doing 50 mph in 4wd. I rarely see anyone discussing the differential drop kit on a 2.5" lift up front.