I'd definitely go ceramic coated... it's worth the extra dough IMHO. You'll thank yourself in about 2-3 years when they still look great compared the discolored or even flaky chrome plating, it has the tendency to bubble and flake and then rusty away much quicker than the ceramic coating.
Overall the ceramic coating just holds up alot better over time, looks better IMHO, and dissipates heat much quicker than chrome (it's also called a thermal barrier btw). If the headers you choose are coated inside and out, even better, not sure which companies only coat the outside... just ask before you buy. I know the Dynomax shorty headers I had were coated inside and out... not sure about the Bassani long-tubes I run now, but it looks like they do also... no idea on the BBK's, but they probably do as well.
The one piece flange that bolts to the heads is supposed to be better... "truer fit" for lack of better term, no warpage or chance of inconsistent fit from the factory.
whatever... I'd say it'd be safer to get the one piece flange, but I've never heard any complaints on the individually flanged versions...
Ceramic just plain looks better
The NMRA real street guys fly with the unequals (1 3/4 though), but I still prefer the equal lenghts if your going shorty-style... 1 5/8" if you plan on running a power adder or doing any serious mods to your ride should be fine