Ok So I actually have a motor coming, they are NLA and it was a pain to source one.
So now I'm for real going to have to remove the tailgate window and motor.
I have see where the rear spring is a problem and that you need to hold the regulator in place while you remove the motor.
Can anyone confirm?
Here's vid
https://www.youtube.com/watch?v=5rqQq9Oj1eA
Note that burbans and blazers are different.