They must want you to drive it in 2nd or 3rd gear for 500 miles! :rofl:
Seriuosly, if you think about it, lugging the car around in 6th gear @ 55 MPH probably does more harm than just driving it with some good sense.
Vary the RPM's, don't just drive it all on Interstate @ 65MPH in 6th; Brisk, but not balls to the wall acceleration, and you'll be fine.