Hrm... that's pretty interesting to hear about you getting pulled on like that.
Stock for Stock, I ran against an unfriendly 04 Cobra on the highway with dealer plates on, and both of us gunned it fairly hard. He only pulled a half car length to a car length on me when we both shut down at 120. We went from about 75-80 mph rolls.
Maybe he was being easy on me? I don't know.
What I do know is that the Cobra and the CLK 55 AMG are the only two cars thus far that have put up a fight that I totally lost in.