Re: Mini batteries? odyssey, hawker, etc
They generally work fine, they have all of the problems that come with sub-sized batteries though, like low storage capacity, low cranking ability, etc.
I think there are probably cheaper alternatives than the link you posted, but that's just because I squirm a little bit at spending $260 for a battery kit. I consider batteries a consumable item, and that's a lot of money for a consumable item. You may totally disagree though.