Tom,
I did my own doors. If you decide you want to do your own, drop me a Email and I will send you all the info. You can plan on about $200 for the parts to convert a door to high-lift. You will need to change the springs, lift drums, lift cables, and add extension tracks. Plan on putting in a liftmaster 3800 opener as well whie you are at it, if you have an opener on the door. A traditional opener will not operate a high-lift door, since the opener wants to go back as soon as the door moves, but a high-lift door goes verticle for a foot or two before it turns to the rear. The liftmaster opener turns the torsion tube to raise the door, and it is dead silent! Don't let anyone talk you into the Wayne Dalton I-Drive opener. It is such a piece of junk that my local Wayne Dalton dealer will not even sell them! The failure rate on them is astronomical!
Here is a pic of one of three doors that I did at my place. The door now runs within 6" of the ceiling, and there is plenty of clearance with the cars all the way up! I can't tell you how many times one of my friends ran the door into one of my cars when they were all the way up.
http://img.villagephotos.com/p/2003-8/339303/FTQWI-P0001848.jpg
Regards, John McGraw