63,
I was under the impression that the two batteries have the same specs. I asked a few questions at the local Honda dealer, and they sort of confirmed it, even though they were very vague on anything relating to hybrids, including how long the Insight is going to be around.
I have an '03 and partly because of the fear of replacing the IMA battery, I just purchased a 100K, 7yr, Hondacare warranty. I've read such a wide range of prices on this battery on this forum that it kind of frightened me. One dealer told an owner of an Insight (out of warranty) that it would cost him $9600! I know that sounds preposterous, and the dealer probably had ulterior motives.