There are some things that lithium batteries are great at. Laptop computers, cell phones, space craft, airplanes, and race bikes where every ounce counts. The Super Tenere isn't in that group.
Lithium batteries also have downsides and trade-offs, just like everything else. For that low weight and smaller size, they cost more, when they come to end of life they will not give warning, it's very easy to cause damage which shortens their life, and if your regulator or charging system overcharges a lithium battery it can go into thermal runaway.
The above is why to me the best battery for the Tenere is going to be a AGM, just like it was delivered with. It's essentially a modern sealed version of a good old lead-acid technology, with better protection against sulfidation and plate warpage, which were the enemies of the old wet cells.
