Do you know what part number your lithium battery is? I might be interested in heading down that path if my OEM battery craps the bed.
Here is the one I ordered on Amazon:
It matches the OEM battery specs for juice. Since it's physically smaller, It comes with foam blocks that will make it fill the exact same space if you want. Instead I took the opportunity to fill a small bag with a jumper cables and a few other things, and used that to fill the space.
The above battery weighs a mere 1.7 pounds. The OEM one weighed 8.7 pounds. Not only is that a 7 pound difference, it's 7 pounds that sits high up in the frame. I could actually notice bouncing the bike back and forth between my legs while standing (I'm over 6' tall).
Also, my OEM exhaust weighed 13.2 pounds, and the Termi weighed 5.8 pounds, so that was another 7.4 pounds. Between the two I saved 14.4 pounds, and my bike is now under 400 pounds with a full tank of gas. Not bad!
Requires it's own charging system, correct?
Not for charging — an automatic charger will work. If you want to use a battery tender, then you do need a special one. You can add the battery tender for only $30.