Great info guys. Thanks all. My takeaway is that there are 3 choices.
1. AGM battery that matches stock specs (330 CCA, 19 Ah), like a Deka ETX16 (325, 19, 17 lbs, ~$100)
2. AGM battery that is lighter & below stock specs, like a Deka ETX9 (120, 8, 7.1 lbs, ~$50) or Deka ETX 12 (220, 12, 12...