I have always believed that you break in an engine the way you are going to use it. If you want it to go fast you drive it that way right from the start.

They way I have always broken in an engine is to fill the engine with non synthetic oil and get the car out on the high way in high gear at only about 35 mph and then hit the gas. At firt the engine us lugging at slow speed and then once you have it at top speed let off the gas and let the compression of the engine slow you back down to around 35 mph. Do this a few time and your rings should be seated. Then change to Mobil 1 and drive the snot out of it.