wow he's a real d1ck. Doesn't even deserve the car he has.
Are you sure its a 535 and not a 550?
I have a JB4 tuned 535 and there is NO FREAKING WAY IT COULD COME CLOSE TO A M5 EVEN IT WAS MISSING ONE OF ITS TURBOS lol
Id say a tuned 550 would put up a good fight but still not be able to pull on a M5.
You should have raped him.