Can't speak to the warranty question, but the OEM battery is a Yuasa YT7B-BS. Same as in my 675 Daytona (the biggest bike it's spec'ed for - mostly found in 400-450cc dirtbikes). Yuasa says it weighs 5lbs, but that's likely dry. So depending on whether you go with the closest Shorai replacement (LFX14 @ 1.8lbs) or the higher capacity LFX18 @ 2.1lbs (as in the Motowheels kit), you're looking at in the vicinity of 3-3.5lbs weight savings. Considerably more capacity and cranking power for the LiFePo batteries though; 210/270CCA for the LFX14/18 vs the OEM's 120. Plus of course no real need for a tender. I suspect it won't be too long before the battery biggies are making these things and putting them in the OEM channel, what with everyone scrambling to get weight off.