Have you played Morrowind? The most reliable way to gain a good understanding of Dark Elf culture would be to experience it first hand in their homeland.
If you don't want to take the time to play Morrowind, I'm sure someone could point you to some material to read on Dunmer, but first, I shall say that yes, there are different factions of Dunmer, in Morrowind, there are the Ashlanders, nomadic tribes that cling to the traditional ways of the Dunmer, you can see four major tribes of them in Morrowind, each of which has a somewhat different attitude, there are the Great Houses, those are the settled Dunmer peoples, at the time of Morrowind, there are five Houses, those are Hlaalu, Redoran, Telvanni, Indoril, and Dres, though only the first three of those appear in the game and can be joined, then there is the Tribunal Temple, the native religion of the settled Dunmer, generally, most Dunmer do not like outsiders very much, but it also depends a lot on who you are dealing with and where you go, the Dunmer in Imperial settlements, of course, are more open to foreigners, and of the great houses, Hlaalu is the most open to Imperial ways, so in Hlaalu towns, people would also likely be more friendly to outsiders, Redoran, on the other hand, is big on honor and tradition and close to the Tribunal Temple, so while they might not be so welcoming to outsiders, they are probably the least likely to stab you in the back, the Telvanni are mages who tend to dislike outsiders quite strongly, many of them are... eccentric, and don't want anything to do with anyone else, so of course, they're not too friendly with westerners, I don't know too much about Indoril or Dres, though.
In Cyrodiil, of course, most Dunmer are western-born, or left Morrowind for one reason or another, so they may not be the best representatives of Dunmer ways.