You can put a BMW 525 engine into a BMW 325. The motor mounts will need to be changed. The 525 engine motor mounts will not match the 325 engine compartment.
under the bonnet
The best oil you could use for the 525 i is magnatec or 20 w 50
The 2001 BMW M5 has a V8 engine.
will a 2001 BMW 330Ci engine fit in a 2002 BMW 330Xi
will a 2001 BMW 330Ci engine fit in a 2002 BMW 330Xi
The 2001 BMW X5 has an inline 6 engine.
The 2001 BMW M3 has an inline 6 engine.
The 2001 BMW 7-Series has a V8 engine.
The 2001 BMW 3-Series has an inline 6 engine.
The 2001 BMW 5-Series has an inline 6 engine.
The 2001 BMW M3 has a 3.2 L base engine size.