Oil made in JB, Johor. API Certified

https://engineoil.api.org/Directory/EolcsRe...ndName%3Dshenzo

no.

suggest you read http://en.wikipedia.org/wiki/Motor_oil#Synthetic_oils

bro, if you read thoroughly (be it this thread, other threads, the one you created, or the wiki page), you should realize that the value before w is irrelevant in Malaysia.

to summary/recap:
The first value before w is for winter viscosity and IINM it's to denote viscosity grade measured at 0 Celsius or 0 Fahrenheit (we won't get that unless you purposely go freeze your engine)

if you want to drop viscosity, max is ~2 notch from your engine specification (try to find the service manual instead of the owner manual), as the second value is typically in incremental of 10, eg: xw20 xw30.
although coming 2015/2016 API/SAE will make 0w16 official

to give you an idea, the Mitsubishi engine 4g15 specified xw30 viscosity EO, while proton specified 10w50 or 15w50. To be fair, engine oil technology and rating/certification weren't as they are today, and iinm it was specifying API SG or something, which we are currently now on SN (alphabetical order, however some alphabets are skipped iinm but you get the idea)
as i managed to dig up the service manual, it gives me the confidence to run on xw30 EO on my year 1999 iswara and till date it has not given me any issues while having pretty awesome acceleration/response due to the lighter viscosity EO