It says in the owner's manual to "drive at changing engine and driving speeds" as part of the 1,200 initial engine break in process. I have to go on a 200 mile each way highway trip during this period. What is the best way to meet this requirement? Use cruise control and change speed every X number of miles by X mph? If so, what would you recommend? I plan on keeping the car 10 years/150K miles, so break in is critical. Thanks.