If you ever plan to buy a garage door by itself without the garage door installation service, be prepared. You'll need to be certain of which track system and which spring system you'll be using. The easier variety are the extension springs, but they require about ten inches of headroom above the garage door and below the ceiling. (Torsion springs, on the other hand, are better for bigger, heavier doors.)
Tracks also come in two main varieties: what's known as powder-coated steel, or galvanized. The galvanized steel is hot-dipped, but doesn't have that appealing finish that helps cut down on noise. Though the powder-coated steel is admittedly more expensive.
You'll also need to make decisions regarding the level of quality you'll want in your steel roller- ball bearings can be sealed in different materials- nylon is much more quiet and durable than steel, but definitely more expensive.
The other problem is that you need to make sure all of these components are compatible with one another. Since these parts aren't marketed to the lay person, you may have difficulty ascertaining this information.
If you have any questions or need help, you should contact some garage door services experts.