About Engine Oil, a lot of variation in opinions. Mostly, whatever a person is using seems to be satisfied with it; whether it is Zic A+, Zic A, Mobil1, Havoline Formula, Magnatec etc. etc.
What i've learned after reading from the internet is that what matters is:
(1) API (American) and ACEA (European) certification,
In API, SM is latest standard and SL is also fine
ACEA splits its specs on performance/economy basis)
(2)SAE grade (viscosity)
5W-30 is recommended for Vitz; 10W30 is also fine
However, about this viscosity thing, some folks treat it as a function of climate. So 10W30 might be better than 5W30 in for climatic conditions of our country.
Following are a couple of useful links: