mayonaise

yeah, that's rational. they could name it anything between 323 and 330. since they already have various models with the 328 designation, it had to fit somewhere below that.

are you simply trying to say that the number goes up as the horsepower goes up? because that's just obvious. either way, i stand by what i said earlier:

go2turbo

Really?
What happen to these older BMW?

1997-2003 540i with 4.4L engine
1995-2001 740i with 4.4L engine
1995-2001 750i with 5.4L engine

Troopa-R

Give the higher output variant the S tag: 330iS. And the turbo could have been the 330ti opposed to 335i.

mayonaise

okay, if you want to be anal about it (please note, i never said they followed displacement absolutely)
a large majority of their cars since they started using their current naming scheme have been named according to engine displacement. since they're offering more and more engine choices now, the possible model names are more limited. however, the numbers still follow the displacement closely. they're off when they have to be.

edit: that large majority is actually around 93% of all 3, 5 and 7 series cars past and present. regarding the models you noted, they are the exception, not the rule.

bunny

What "horse power" figure do they use? You see, the "horse power" is actually a power band function, i.e. an instantaneous number at a given rpm. It would be simply stupid to tax at the peak number. It will just discourage high rev high peak engined cars.

Tax by horsepower is stupid. If they want to save the enviornment, they can add tax to fuel.

Designation by imaginary displacement is stupid too. But still the most stupid thing is to have 42452 models within the same series/class.