The door quotes were from a local company that installed a new door in my garage about seven years ago. The sales rep is the one telling me how much clearance I need. The doors aren't a priority to be honest, but once I get a few things figured out I'll be ordering them. Lead time is about 3 months so not bad.I have a 10' x 10' door with a double torsion spring set up with an 11' ceiling height and it uses regular tracks. It is a steel door with insulation between the 2 layers of steel and 2" thick. The track is mounted right to the ceiling. On my rear overhead door, it is a 9' x 9' x 2" insulated door, and that track used to hang down from the ceiling. I have since removed the track and am going to install a Liftmaster sidewinder door operator since it will give me more height for a car on the lift when the door is closed. I would suggest that you talk to the door installer before ordering the door, and he can give you a better understanding of your available options. You also might get a better door for the same or less money from a local door company. When I built our home, the contractor that I hired gave me a price for the doors, and I checked with a local company, who gave me a better price and a better door. When I had a problem they came out and serviced the door at no charge, since they sold it to me. Another thing to think about is that a local door company orders doors by the truckload, and should you need a replacement panel because you happened to run into the door, they can replace a panel from inventory, versus having to get one from the company supplying the building to match.