Anyone Install Lithium ion Batteries? Results?

no, the main advantage is weight and size. I have a 1 kilowatt pack I use with my recumbent tadpole trike that I motorized. It is about 12 pounds vs something like 60 pounds for an equivalent lead acid. I can draw about 400 amps from it if I wanted (but normal draw is 2 or 3 amps while pedal assisting, maybe 20 or 25 amps going up a steep hill). My pack is made up of Lipo though...I wouldn't sleep anywhere near it...I store it in a vented steel box on a concrete floor at home.