ill chime in.
i bought a gallon of herculiner for this purpose aboot two years ago. waited for a decent day, but one never came. (washington, go figure). so on a somewhat non rainy day, i ripped the grill cover off the truck and gave it a few coats. put the lid back on, which was a mistake. the can basically sealed itself shut. so if you arent going to use all the product, be aware of that.
now, i started to notice after a couple of months, with little actual direct sunlight mind you, that it was really faded. so i thru on a coat or two of semi gloss. that seems to hold pretty well. so we finally get a few nice days here and i go to do the back. but the god damn can is sealed itself shut, so i end up poking a hole in the can/lid and get just the solution with none of the little chunks. didnt really bother me. seems to be holding up pretty well. i basically just masked off the plastic parts and had at it. has a little runs here and there, but this aint no beauty queen, so dont really care. i would recomment the herc, as its got the chunks in it, is fairly inexpensive, and aside from the fading, is pretty durable. i would also recommend very good prep work too and as stated earlier raul said, the primer. altho they say its not needed. cleanliness is dogliness.
for the front bumper, i used the duplicolor spray on shizz. the verdict is still out on this, as i dont drive the truck very often. it looks pretty good. seems to spray on good. i think i got about 3-4 coats? maybe. let it dry/cure completely before you go and bang it around.
sorry for the long post, too many tekillyas