Hey, I just bought the same stuff from home depot yesterday! Gonna get to mybig shop door this week. Those panels (4'×8') weigh just over 4 lbs so weight is not a problem. As for around the edges they make a plastic and rubber strip that fits on the outside and goes up against the door. Or in my case with a big slider (11'×11') I'll make a 2" strip of the same insulation and nail it on the inside of door frame.
This thread got me thinking about my insulated Raynor 20 ft wide - 10 ft high door. I have an in floor heating system for my garage and it is 67 degrees (6 ft off the floor)(concrete 80 degrees average ) It is now 17 degrees outside reading from my Davis weather station mounted on the roof. I took one of my MAC tool infared heat guns I use with my race team for engine - turbo diagnostics and shot the door on the inside. 63 degrees. Went outside and came up with an average of 20 degrees. Very impressive on a windy cold night. This door really helps with summer heat also. If one lives where I do I think the investment of a reputable door manufacturers insulated door is a real plus. They may cost more at first but on a night like tonite, worth their weight in gold. Understand most of you don't live in the cold like I do so not justifiable. Thought I would add my little scientific adventure to this! Rob