Q. What is major difference in Yamaha r15s and R15 3.0

Seating posture for R15S is less aggressive which means lesser wrist pain, lesser back aches and the halogen headlight assembly facilitates you to later on modify the headlight to a powerful bulb set up where as on the V3.0 its out of the question. The V3 is somehow heavier, feels aggressive when seated. However V3.0 has slipper clutch, the looks of the new R1 M (almost), has wider wheels, slightly better performance, better mileage (debatable). On the comfort front V3 is not suitable for touring or long journeys at all.

Both are totally diff bikes r15s is basically the same old V2 with a single long commuter ish seat also less on power ...while version 3 on other hand is all new 155 power mill with VVA which has good power overall..

R15s is better in sitting comfort