Lithium Batteries - Light Weight vs Cost

For a 3100 pound car, I don't think the weight savings is worth the cost and additional worry (over charge, over discharge, etc.) and maintenance (cell balanced charging).
I run them in my motorcycles and even there, I didn't notice the weight loss.
They do work well though, especially if there is no key-off current drain.
I like EarthX batteries, FWIW.

Thank you for the good advice, jmardy, and thank you for sharing your experience. Much appreciated!

I purchased the  AG-ATX20-RS for my Ultima, 680 CCA and more than enough power to turn over and start the 600HP 10.5 compression V8 after a long rest. The car hasn't truly been recommissioned yet to know how  it will hold up over time, but at $287 it really wasn't any more expensive than the previous Odyssey PC1200 and the new one of those I purchased was dead on arrival.

  I'm curious, has anybody seen data that shows cold performance? Lithium ion thrives at 25'c and performance will drop as temps get higher or lower....For a car exposed to Freezing the power from the battery is hindered significantly and may prevent a start.

  At least, there is nothing about the specification here that suggests less than  responsible engineering and care, esp the comments on "cell balancing" and detection for safety, the use of only UL approved Cells...It also seems that the design actually works at low stress--meaning, the battery cells are operated actually below their 'nominal' voltage. This is one reason that the costs are higher (since there is a lot of potential capacity in the pack that is available, but not used), and I'd think longevity on these would be very good (more than 3 years...)--Lee

The Antigravity battery I purchased has a CCA (0 degrees F) of 680 Amps. Most of the data speaks to EV battery performance and not as an ICE battery. The LFP does not suffer from being fully charged and typically has a greater cycle life.