the round airbags wont work on a 328ci sorry. but i have seen ernie (erni323) get this on his ride, eventhough everywhere else ive talked to says this wont work on the 2000 models (maybe the sedans are diff).
basically the reasoning is that when bmw adopted the 330ci one of the new upgrades was its air bag system. it isnt that its jus round now, rather it is running a dual stage deployment (like the five series). now the first gen coupes (again i dunno bout the sedans) run a single stage deployment. so even though u can plug in the airbag (with a corresponding steering wheel) the ECU has no clue what to do with it, and ull get an airbag warning light, and an airbag that wont work.
hope my info is right, cause i thought it was till i saw ernie's car, so i dunno...
(pick 2 of the three only)