lets say, Myvi is "a betta car IMO" compared to BLM. Myvi is around RM10K more expensive than BLM.

and lets say, you travel 20K KM per year. With BLM, RM0.2/km, that will mean RM4000 worth of petrol. Lets assume that Myvi can achieve RM0.15/km, that will mean RM3000 worth of petrol.

Every year you are only saving RM1000 on petrol. So you need 10 years to breakeven, given that by then you still have not fed up with Myvi floaty "handling", lousy trunk space, and hot back seat.