My understanding is that they were all steel (except for Titania which was titanium, and if you find one of those grab it, or tell me about it and I might!) through 2004. In 2005 Isis only was offered in titanium, other models were still steel. 2006 is the year they switched to aluminum (with the exception of Fast Women who has always been steel), bad news, some were even recalled due to frame failures. Then in 2008 she returned to steel for the entire line, which are being manufactured in the waterford factory.

I have owned (2) 2001 steel classics, a 2003 steel Isis, and a 2005 titanium Isis, and they are all 9-spd. What I can't remember is exactly what year they went to 9-spd, it may have been 2000 but not 100% sure. If you have more specific questions on a model you are considering, feel free to PM me.