My experience with vibrations.
I had started getting some vibrations on idle. Nothing severe but irritating.
Best change came from airfilter. The day I put in a geniune filter (worth 2500 and definitely can tell by the finish) ... vibrations gone!
Also do the idle calibration given in this thread. If you dont find it simply google Vitz idle learn pakwheels.
Run recommended oil, good plugs, clean original filter and good fuel. Not necessary to get HOBC, but dhang ka pump ho. Im using HASCOL in Khi n car is far happier on it than PSO, Shell or Total