[Misko_Hryzko]

By comparing 320iX (B48C) and 330i (B48D) on RealOEM I found differences:
- engine block
- different turbo
- intake manifold system

The rest like heat management, cooling system, lubrication system, timing chain, belt drive etc. seems to be exactly the same.
I guess the biggest difference is the turbo boost pressure. From these pictures it looks like the biggest difference is not the turbo size but the outlet pipe diameter. The one in 330i has 4 separate chambers while one in 320i has 2 parallel ones. The diameter of these pipes are much bigger in 330i allowing for higher air flow and pressure.

So 320i (B48C) is not just de-tuned 330i (B48D). But 320i (not xDrive) manufactured before June 2019 had engine B48D (I tested one) with the same turbo as 330i today and that's why it looks like only de-tuned.