Theoretical, Practical, or Wild Ass Guess
The voice in the back of my mind says use the Shorai. Why? It's lighter. Really that is the ONLY positive advantage I see. The AGM is easier to maintain. No pricey special charger. I can plug in my charger to the AGM and it keeps the voltage OK even in a cold garage (it hardly goes into the 20's all winter in SC). The AGM fires the bike up better, IMO than the Shorai. I am going to run a test, a kinda, sorta practical test. My radar detector drains the battery a lot. (that is another mystery, but it does). I'm going to keep it plugged in and measure the battery voltage at various times, then just see how it cranks. Going to do it for both batteries.
Old, but not Dead