I did most of those things you mentioned; lithion battery, Zard exhaust which is about 5 lbs lighter and that's dead weight. Seems to run better, definitely smooth and lively and better mileage, slightly better, since I installed the Zard. Also have home-made air filter out of Unifoam which is used by motocross racers. Getting 50mpg, except when loaded for s'camping - scooter camping - when I carry a tent, bedroll, water and food.
Haven't tried the burger thing, because I don't eat burgers often, and when I do, I prefer veggie burgers. Coffee now, well, that liquid is pretty heavy so I try to leave as much of that behind as possible.