I live in sunni country, praying method calculation is diferent compare to Jaafari calculation. Example for Subuh the time is delayed by plus minus 15mins and so do maghrib plus minus 13mins. Can I perform recommended subuh prayer before the exact jaafari praying time because I might miss the Subuh congregation prayer with them?

There is nothing called Shia and Sunni timing for Fajr prayer. Normally, the congregation prayer takes place after 15 to 20 minutes from Azan, which is fair enough.