Do the lithium batteries require any special charging equipment in the car, to prevent overcharging, etc?
Or just a tender for when it's sitting a while?
No special charging equipment is needed for the car, but you do need a tender for lithium ion batteries. A "regular" tender won't work.
How well do you think it would hold up if you had to crack the car several times to start it with E 85, and does the car feel off balance? I think I remember some saying that a light battery causes the car to pull to one side? True or not true? Thank you.
How well it will hold up depends on which model you buy. Antigravity has three different models in the category mine came from: 16 cell (480CCA), 20 cell (600CCA), and 24 cell (720CCA). The larger you go, the heavier the battery (not a big deal since the 24 cell is only 6 lbs and the 16 cell is 4 lbs). But you get more CCA and more amp hours when you go bigger. I went with the 24 cell and feel very confident that it wouldn't skip a beat in the scenario you asked about. And definitely not true about the car pulling to one side.