....... but don't use a fully synthetic.
Apart from the cost (!), why not? I would be interested to hear if there is any specific requirement for the Vitaras.
We went through this relating to the classic Mini some years ago and the outcome was that as long as the viscosity was correct, semi or fully synthetic will do exactly the same as standard oil, but retain it's properties longer. I spoke to Castrol and the chap was very helpful and came across as being totally unbiased. The letter we got from them is reproduced on our web site if it is of interest.
http://www.dsnclassics.co.uk/misc-tech-oil.htmlBear in mind this relates to the BMC A series engines which are a much older design than the Suzuki unit. But the basic principals will still apply.
Personally, I just use basic oil and change it frequently.