tsm - i'd take them a little higher than 165 degrees. at that temp, they will technically be done, but cooking meat until it is done and cooking meat until it is barbecue are two different things.
jeff recommends an internal temp of 172 and this works pretty well. sometimes i go a little higher, but not much.
as far as cooking temps, i'd recommend closer to 250 and farther away from 225. ribs can take a while and it is possible, depending on many factors, that low temperatures will give you the beginnings of jerky rather than barbecue. also, i've noticed that in the 230-250 range, some really good things happen to meat in a pit.
as far as 321/foiling ribs i personally don't, but a lot of people do. my recommendation there would be to try ribs both ways and see what you prefer.