New engine break-in procedure

I recently purchased a 95 M3 with 65k on the body and a brand-new factory installed engine. Obviously, I don't want to lose my warranty by beating on the engine albeit very tempting and I also want to ensure that I don't develop any performance degrading ruts inside the cylinders. I've been trying to excercise a full range of motion through the engine while not exceeding 4000 rpm. I'll typically take it out to the highway and push it to about 85 mph before letting the car naturally decelerate to about 60 mph before accelerating again. I've only put 200 miles on it so far and I plan on pushing the car to about 60% after 500 miles and eventually I'll excercise its full potential once I put 1500 miles. Is this the correct way of breaking in a new M3 engine?

Sounds like you're doing all one can these days, given the current strict [excellent] engine controls.
AVOID prolonged idling ! ! The oil flow is important.
With earlier carborated engines it was easier, nice fat amount of fuel wash on accell. to set in the rings and super low crankcase pressure on decell. to recoat the walls with oil and start it all over for another cycle for about 100 miles.
The materials, oils [to some extent] but mostly the engine control systems are so good now you have little control over these things anymore.
Keep the idle up for a little while and drive it just like you are.