So I've search on amazon and ebay for these Samsung infuse compatible extended mah batteries, but does anyone have one? If you simply amazon it, more than 10 different batteries come up saying they are Samsung infuse compatible and they are all different prices. I understand there is not a Samsung brand of extended battery, but can anyone give me any advice on these extended batteries such as the 3500 mah batteries and if they work, if they damage the phone at all, which one is the right one to buy if I decide to get one, etc? I have a casemate case that's sold at the AT&T store. Will I need a new case because the back won't fit anymore?