gmm: in all honesty, most people couldn tell you an f355 from a 360 from a maranello. I think that the simple fact that it's a ferrari might draw attention.
As for the car itself, I plan on keeping the M5. The 360 is more of a toy (while almost everyday in useability). I don't plan on taking to the shopping mall, or the grocery store, or what have you. Car meets, enthusiastic driving, and Marin (yes basil!) are what I had in mind. And maybe taking it to work.
To every man his own, and I do love the 550, really. 485bhp is intoxicating to say the least. My personal take is that the M5 has the everday civility and comfort, and I'd love to have a convertible (especially one that goes

)... so why not start at the top?
--Dan