This is the first time I have seen someone weigh their s54 swapped e36. I'm going to weigh mine (has almost zero intentional weight reduction on it so far) on a friends corner balance scales soon and start a spreadsheet to track changes to the car and its weight. For batteries: I have had lifepo4 in a street car before and it can be a hassle to live with. Also your hold down hardware/bracket weight starts to become a significant percentage of your battery weight so consider looking at that too. If you go that route make sure you aren't pulling any current when the car is off or you have a battery cutoff switch that is easy enough to access that you will actually use it. It's very easy to kill one of these from over discharging and they have comparatively very low capacities. Also I haven't looked into brands in a while but shop around and try to find some dissembled images of different batteries. The braille batteries I have seen internals of were really bad + expensive. I haven't seen anyone tear down an antigravity battery but I'm sure someone has. Realistically these battery companies are buying cells or pouches from the same factories as everyone else and assembling them and marking them up different amounts. I had an alien motion and was happy with the cost and construction quality. If you can find a large enough cylindrical cell based battery I think those are a better route than prismatic pouches but they are less common now.
