You know, when you buy these cars from the lot, brand spankin new, the really never say "take it easy for 500 miles" and the gears usually only have lot miles on them only. Breaking in engines/gears is allways a prudent idea, but the fact is, that you probably could start driving them whatever way you will eventually drive them, and the percentagages are waaaay on your side that nothing bad will occur. It would be prudent for you not to power drop them or bang the heck out of em till you have a few hundred miles on them, but other than that? Just drive.
2005 Torch red, predator 93 octane, K&N filter, Pypes true duals, Eibach Pro-kit springs,4.10 posi 8.8 rear end. GT fanblades with Eagle F1's, GT500 rear bumper/spoiler/front splitter