Hi delsoo. If you have read the links zeng posted, you would see petronas oil is well respected worldwide. You must understand Petronas isnt a 2 bit local company. They partner with world class blenders and hire some of the worlds best engineers..etc.
The only malaysian companies that i have no confidence in are..mazlub, jtx,hardex,platinum oil..jetron..you know what i mean..

I have tried BHP Syngard, nothing much to say about it, did not do a UOA, and i will probably not try it again and and have no incentive to do so.
BOSCH, Bardahl should be good oils, again , never tried them. Lexus , I dont know. Mitsubishi i heard is packaged by ENEOS and the full syn can be had for RM99 on sale at AEON. seems like a good buy , but the shear stability might not be up to par with Shell. Its a 5W-40, so if the shear stability isnt good might go down to a 30. Only way to know is do a UOA. May try it in the future but as I have already tried CASTROL 0W-40 and Shell 5W-40 and results are almost the same so I see no point in trying a other brand 5W-40, its probably not gonna do any better.
I am trying a 30 monograde now, just to study the effects of oil with VII and one without.