I'm about to pick up my warranty-replacement Shorai...after the 1st one failed and eventually overheated while receiving a <2 amp charge. I loved the speed it initially spun the DRZ, but it never had any longevity and responded very poorly to any charging(less than 1 amp, as directed by Shorai) It would die in less than 7 days with only a very minimal load
It was a hassle dealing with Shorai as they want to physically handle the battery before warranty(ing) it. Eventually they gave in to my badgering and shipped it, but only after I went stateside to ship the failed battery back to them.
In the end, too many dollars and too many hassles.
Of course others have had more success than I did