Found this chart for Suzuki owners showing recommended grades from HKS. May help people to determine proper oil weights for their cars as recommended in Japan.
https://www.hks-power.co.jp/en/product/oil/list/suzuki.html
In my case, a DA17 Suzuki every R06A turbo..... 5w30 is the recommended grade.
Oil lube shop has been pouring 10w40 here, but next change I'm going to switch that out. However, still confused if 5w30 or 5w40 is better for Pakistan thanks to the hot weather. Websites say 40 weights are better for hot climates and busy/high revving engines.
My guess is, no one really knows and that it doesn't really matter. I'm going to try 5w30 next change and see how it goes