The 850csi is one of the sickest cars ever made. The 850i had about a liter less of displacement and put out about 80hp less than the Csi (380 vs. 300). Any and all of the 850s were awesome performing cars though.
Check out www.e31.net , the videos section is insane. There is one of a panic stop from 155mph!!!!
You should have smile on your face if one of them backs down from you. I am sure the Csi would have been a different story