I hope I don't get thrown out of here cuz I'm not a manufacturer but my suggestion is to get the tire carrier. Later you'll be glad you did. The tire carrier is sooooo easy to manipulate (my 4 year old loves to "help daddy open the door").

Then, later, when you need space for a air tank, you'll have that (or whatever else) and an awesome departure angle to boot. And tow points. And a receiver hitch. And the ultimate protection for a "rear end". Need I go on?