I am the proud owner of an M5, but made the mistake on taking a drive in a buddy's rs4 the other day..
Not too shabby, and much faster than I had originally anticipated.
I haven't checked the official 0-60 stats, but it gets down!

Anyone else own or driven one?

 

sat in an RS4 before but never driven either one or in an M5. Thought the RS4's seat was more comfortable than my sport seat. Wish I had picked the comfort seat version.