Q. What are the major deference among these three variant?

Royal Enfield Meteor 350 is available in three variants: the base Fireball, mid-spec Stellar and the top-end Supernova model. Fireball is the most basic variant of the lot, and thanks to its basic equipment levels, it bears the closest resemblance to the erstwhile Thunderbird X 350. The Stellar variant gets a chrome-finished exhaust system, a rear backrest and 3D tank logos. The range-topping Supernova variant gets a large front screen, diamond-cut alloy wheels, dual-tone paint schemes, and contrasting seats. For more details, check out the following article: Royal Enfield Meteor 350: All You Need To Know.

Cosmetics thats it stella gets visor and a brushed metal rims where as supernova gets all chrome parts visor and a backrest

Cosmetics thats it stella gets visor and a brushed metal rims where as supernova gets all chrome parts visor and a backrest