See the tech curb of a ol' M54B25 engine (525i MY '03 - '05) and the even older M52B25 engine.
In spring '05 the 525i engine changed to a 2,5 litre N52B25 (218 hp).

The current engine (since March '07) for a 525i is a 3 litre N53B25 giving 218 hp and 270 Nm.
In US the current 528i has the older 3 litre N52B28 engine.


Just for comparison I give you the N52B30 (530i MY '05-'07) and the N54B30 (current 535i) curbs.
In EU the current 530i has a 272 hp@6700 rpm and 320 Nm@2750rpm N53B30 engine.

Is this confusing enough?
.

Is the 525i a 3.0i ?! The same for the 325i ?

Wondering if it can reach the power of the 530i with some mods at the engine ...


PS:
Nice avatar :D :D