FWIW - any we know this is controversial
http://www.mototuneusa.com/break_in_secrets.htm
The key is loading the engine. Full throttle for 80% of RPM while in 3rd-4th gear, while in the first 20 miles, with engine warm.
All my bikes and cars are done this way and personally, I feel like my 328i N26 is much stronger than the loaners with same motor I've driven
I personally subscribe to this method on the street. If you're gonna run it hard, make sure it's warmed up and make sure you have space to do it while your tires and brakes wear in.