Interesting exchange. I wonder what motivates that particular kind of aggression and crass behavior? My guess is the 535 driver has a huge chip on his shoulder and this is how he acts out. It's his way of coping with envy and jealousy. Perhaps some deep seeded insecurities? Who knows...
Back in my day, if someone came calling like that and you pulled their punk card, you'd discover one of two things. They just wanted to see your car run knowing they'd loose just to size you up and have fun or they had some serious tricks up their sleeve like a hidden multistage N2O setup.
Lets consider the second scenario and give the engine enough latitude to assume it will hold up to the power. Lets say this was an AWD 535 with a tune, exhaust and a well engineered N2O setup. My guess is it would be quick off the line and build considerable power and torque throughout its RPM range. This would make 0-100mph a pure traction contest. A contest the M5 could loose?