I would recommend purchasing a PZEV rated HCH I (if you live in a clean state), not only for the better emissions rating, but you'll also get the PZEV 15 year/150,000 mile warranty on all the hybrid components (10 year/150,000 mile warranty on the battery), that is fully transferrable.

Here is the 2005 HCH warranty list:

http://www.ahm-ownerlink.com/Documen...t/apl27540.pdf

I wouldn't be too concerned with the battery pack, but I would be concerned with the catalytic converter failure that some of the early HCH I's suffered from (that the ECU reflash should have cured). If you purchase an HCH, I would confirm that this reflash has already been performed.