What can being careful do, besides waste a few miles of potential fun?
I say take it easy on any car for the first 500 miles, or however long after that it takes the brakes to become naturally soft(if you've ever driven a brand new car: you know what I mean)....as in, a 500 mile road trip doesn't count :p.
No high rpms...which means naturally, no quick acceleration all the time. But I don't understand what a sustained speed can do to an engine that's harmful...
Whether it actually does anything...that's how I treat all my new cars...and will continue to do so.