is the 13ft inside or outside dimension? if outside with a single door you can get up to about 11 ft or so to account for the walls(if framed not block) and the door mounts. if it is inside dimensions then you can go at least 12 ft. i have not sized doors lately, so not sure if that is a standard size or not. my doors on my house are not much over 8 ft each and my Dodge 1500 4x4 just manages to get thru with about 2-3 inches per side mirror clearance.

one mistake people make is not making the door HIGH enough. my truck is factory height and i have 3" clearance for the roof coming thru teh door. i see vehicles parked inthe drive around here alot due to garage doors being too low to get a factory height SUV or minivan in there!

This sounds like a custom job, are you going to be the one installing the garage door? If you don't have much expertise you are better off calling a local garage door company, that way you will save yourself some time and money.

Here is a link that might be useful: Garage Doors