Is there any point in trying to scrape together 16,000+ gp to try and buy this in Chapter 1? I heard a rumour there was some sort of plot effect, but don't want to spoil the game by reading thru' walkthru's to try and find out. Ta

Unless there are two distinct ring-related plot twists for Aribeth, then that's the wrong ring. As I recall, the plot issue has to do with another ring that she might give you in chapter 2. There are free items you can get or find that offer decent spell resistance (Grimgnaw's amulet gives you 10, for example). Sure, 16 is better than 10, but you don't really need it in chapter 1. I think you can buy the ring of the wood elves from someone else in chapter 2 if you pass on it in chapter 1.