Bigger garages will be available to purchase in the game. People who purchase the special edition or better, will receive a bonus special garage instantly. This special garage will be larger than the normal garages that only hold two cars.
Half of this response is based on research and the rest of it is my assumption. Lets be honest though, it makes total sense.
Special Edition does not get any extra vehicles or garages. SE gets the single player clothes/tattoo, stunts missions, steelbook, physical map, extra/free single player weapons, and the single player 25% special ability boost. No single player bike, hot rod, or garage. No online garage or car. No online additional character DNA from previous GTA to "make" a new charater on the online play.
Collector's Edition get's the exlcusive bike and hot rod in single player, plus a garage. In addition to getting everything the Special Edition gets, the CE get's a high end (electric) car and a garage online. Also, CE get's exclusive characters (DNA) to choose from when creating a charater Online.
To answer J. Gillen: That's unsure as of right now, but it's unlikely anyone but people with the CE will be able to access the garage with the high end car in it.
However, there will most likely be other garages you can buy online, (it would be insane if they didn't) but you will not be handed one right off the bat like you would if you had the CE. The garages will likely be spread across the map, and you will need to go to each individual location to get each garage's vehicle. The CE's Garage will likely be in a building that you need to be "keyed" for to get into; thusly, only people with the CE will be "keyed" and able to get into that particular garage, but there will be other garages that you can buy in different locations. This is mostly speculation, but from watching the game and from previous games this is the best I can gather.
Thanks everyone for responding! I went ahead and cancelled my pre order here and pre ordered the CE. How do you guys think i would be able to get these garages from the start? maybe a little card with the code on it? Im super pumped for this game anyways. I really wish they included a season pass in the CE.
Likely a code, yes. Then at some point early in the game (if not right away, b/c R* claimed the map is entirely open from the start) they'll make it pretty obvious where the garage is. Definitely an icon on your in game map if nothing else, for sure. I too am pumped, that's why I talked myself into getting the CE as well. I figure I'll be spending a lot of time online to justify the more expensive purchase.
This and Rocksmith (2014) will eat all my free time for the next 12-15 months. I have high hopes, and from what I'm told, it will be as good as everyone hopes.