UPdate - new battery and bluetooth 12v monitor installed last Monday night, all good since then including one day with 40 miles of driving and recharging in weather well below freezing (16 to 28 F), but I happen to be mostly driving other cars the rest of the time since.
FYI, altho I ordered from Remy, the sticker on the battery I received says [Deka Intimidator EHP](https://remybattery.com/batteries/brand/deka-intimidator-batteries.html?srsltid=AfmBOorxsFi7eoMbizQPDMsF1q-32WuvMxLPyiLSgftX8ExWmqHWSfq4). IDK if there's any functional difference - it seems to have the exact same terminal connections as the OEM BMW battery it replaced.
Also FWIW, despite no indicator on the shipping box for 'this side up' and it clearly getting Ace-Ventura'd around by FedEx, it did not leak or show any signs of damage inside the shipping box. It was well padded with foam made to fit the battery and fill the entire shipping box. So far I'm happy and the car seems to be too.