Ceramic helps a lot, but its not necessary. If you have the extra bucks, go for it.
Yes, 1 7/8 will hurt a little, not dramatically. But why get them if you do not plan on boosting your truck? They will not help until you got a power adder so its really pointless to go with them (maybe JBA only come in 1 7/8"?).
Also be aware as another user found that you may need to recenter the engine to get the headers to clear the steering shaft. JBA are cheaper for a reason. They are not as good material and finish wise as ARH or SW and they also do not fit like either. Plan on running into an issue if you go with JBA. If you dont mind saving a few bucks, and possibly spending more time installing and fighting with them, then by all means go for it.