@umans
Yes Dear as you mentioned it is safe to switch over to other brand while with out changing VISCOSITY GRADE, but one thing you should keep in view that never go back in API GRADING, like if you are using API , SM GRADE then try to remain in API SM, GRADING some time not all times it can cast some nagative impect on the machine. Secondly as ZIC HIFLO, API SM, SAE 20W50 is the best option while using oil having grading of 20W50, then you don't need to go for other options, any how as you mentioned it is not unsafe ,and as you asked which oil is best for your car i recommend you to keep use ZIC HIFLO,20W50, API SM,GRADE,(Retail price: 1450/-, and i sugest you to visit our service stations 1. Wahdat road , 2. Johar Town near Shoukat khanam Hospital . for appointment pl. call me @ 03444445936. for further guidance.
More over where GEAR OIL is concerned you should replace it after ever 40k as recommended by OEMs. It is a famous misconception amoungest our most Techniciens bro that gear oils should not be replaeced" is wrong
So always replace gear oil after ever 40k. Our ZIC GEAR OIL GL-4, 75W85 is recommended by PAK SUZUKI MOTOR COMPANY TOO.
And lastly the prize of Gear Oil is 392/Litre.
thanks you very much and at the end sorry for my late response