XLT is a trim level. It basically means chrome bumpers and carpets.
XL= POS base model, rubber floors, crank windows, etc. V6 or 4.6 v8.
STX= shit model but has body colored bumpers, aluminum wheels and foglights. 4.6 v8
XLT= nicer equipped truck, carpets, power windows and locks, chrome, optional 5.4, etc.
FX4= even nicer, has skid plates, full power, optional leathers, etc