We had to replace the opener on our old house about 4 years ago. Standard 2 car garage door and opener. The cost for the replacement of the opener (labor and parts) was about $600.

I almost had to replace the standard size 2 car garage door on my new house 6 months ago. I was quoted $1200 for the door. It could have been up to $3000k for the door if I had gotten very fancy with insulation, windows etc.

So if they are doing two custom doors and openers I could see the quote being as high as $6500 if you are getting nice doors, but if you are just replacing the openers you should be a whole lot less.