Of course things could always be better. Typical battery got me 3 years, AGM, 5.
The aggregated cost over five years amounts to $72 per year. In CA that’s not even a tank of gas.
Don't know their origin.
I did, I've got the Odyssey 20amp charger. Five west coast summers and mountain winters I call a success. Became weaker to start and didn't respond to charging... figured with winter approaching it was time.
Yeah, adding preload usually takes care of a lean, but if it will work for you, who knows? IIRC, Lexus has a spring solution for KDSS lean, so it's something they do.
I've got all the fancy stuff, never use any of it. The GX is already awesome, so the tech feels like it's just there to make the trims different, not actually make it better. Enjoy your rig in its purest form.