Well, this question has been asked about 158 thousand times already. If you want to see some posts, check out the TI Discussion Groups: 89/92+ because there's always some post there about exactly that. My opinion: definitely worth it. But keep your 85 because my calculus teacher has basically banned the 89 from all of his tests (despite the fact it's legal on the AP test). ~Dave <the_regul8r@bigfoot.com>