I've had that Sears battery for over a year now. No issues at all. I registered it with the one stop coding cable but it was a major PITA to get it working. If you're not tech savy, I would say go for the Bav Technic cable. Its more expensive but should be way easier to use. The only bad thing is that their software only works on older computers. If you have USB 3.0 ports, it won't work.
09 E90 M3 - Interlagos Blue / Black Novillo / Sycamore Anthracite / Eibach / HRE