Originally Posted by KingOfJericho
The 335is is currently listed on BMWUSA as having a twinpower turbo, the same as the N55 335i. The same is listed for the Z4 35is. I believe the N54 is already a thing of the past.
BMW uses the TwinPower turbo marketing term for both single dual scroll turbo and twin turbo engines.
It may be that the 335is will change to the N55 (or simply go out of production early), but as far as I know this has not been announced and is not the case.
As someone else mentioned there is also the Z4 35i and 35is which both still use the N54. However, I don't think we have 2013 Z4 information yet, so a change to the N55 may be in store. It would mean a drop in power for the 35is though, so I am skeptical of the N55 for that particular model. It seems it would be more likely to see it simply discontinued.
The 740i/iL also still uses the N54, but that is all but certain to change with the LCI which is imminent.