i had the pleasure of driving a 458 Italia for about an hour a few months back. it's a very comfortable, livable car that will put a grin on your face that an M3 never will. it's not any lower than my kW equipped M3, and the 7-year maintenance eliminates the biggest objection to owning a Ferrari.
the only downside is 2 less seats and it's not for people who don't like attention. it may be diminishing returns performance-wise, but the car gives you a feeling that no BMW does