My diagnosis (only my guess - might be wrong)
Car was built in 1998 - really should trust the Realoem.com.
Was first registered in 1998 or 1999 in UK or Japan (Realoem says Europe so might be UK)
Grey importer in Malaysia declare as 2000 car to increase price - I'm sure there are ways that they can do this
First registered in Malaysia in 2006
Explanation for the M54:
Might not be a M54 at all. It could be a M52TU engine which was first produced in 1998, which tally with the year of production of the car. It has double vanos and looks very close to M54, and looking from the top one couldnt easily differentiate between the two. Aluminium alloy engine block. Could be: M52TUB25 engine in its heart.
This is M52TUB25 engine - who can tell the difference?
http://en.wikipedia.org/wiki/BMW_M52
Also from the interior shot, for me its likely to be a 1998 model.
Any comment? What do you guys think?