nevermind how i ordered 2....
i didnt order the plastic battery box that you are looking at though...they wont allow that on tracks, at least for the organization that i go with.
anyway, i have the black aluminum battery box from summit for $89.95 and the cable kit for $43.95 i think. If this is not what you are looking for, i'll just go ahead and return it.
tips on how to do it...rather simple actually, takes about 30mins to do. hardest part would be after you put the battery to the back, you need to somehow tighten down the fuse box cuz it'll just kinda sit there after the battery is gone (the fuse box is attached to a bracket that connects to the battery in the front).