I had very good experience using nitrogen in all tyres. I have been filling nitrogen in almost all cars which I have bought since last two years. I have experienced that my average has immediately gone up after filling nitrogen as well I dont have to check the pressure again and again. once in three months is sufficient to keep check. I had dzire diesel earlier, before filling nitrogen it was giving avg of 22 on highway and after filling nitrogen it started giving 25 on highway. For filling first time, they charge Rs. 100 for all four tyres, and later on for top up they charge Rs. 30. & i feel spending rs. 30 on quarterly basis is not a big deal.