1)Which synthetic engine oil do you guys use for your E36?
Anything that surpass MB229.3, LL-01 & ACEA A3.
Weight Xw-40 for better high-temp viscosity, HTHS, and better oil efficient.
2)What are your service intervals?
10,000km. Is easier to remember.
3)How much does your oil cost per bottle?
Whatever is the cheapest. Castrol EDGE 5w-40 is great price at RM150/bottle.
4)Where do you get the oil from?
Anywhere as long as is cheap.