Break In Secrets--How To Break In New Motorcycle and Car Engines For More Power
this method would definitely be considered aggressive. please note that it does not involve redlining the car or being harsh. just accelerate aggressively and engine brake.
to me, what is mandatory is 1: varying speed/revs during break in, 2: not putting in synthetic too early in the car's life, 3: warming up the car before driving hard.
after that, who knows what makes a difference?