I asked this just to be sure:
Will these vehicles also be obtainable in the normal edition of the game?
Thanks for taking the time to email us, we're glad to hear you're looking forward to GTAV. Currently, the only way to guarantee access to the digital content from the Collector’s Edition or Special Edition of the game is to pre-order or purchase those specific versions.
So for those who really want all cars/bikes, better make sure you pre-order that Collectors edition fast!