97 astro - replace window motor

Is it best to replace the window motor with the window in the open or closed postion? Will there be tension on the spring?

I did mine with the window partially lowered. It doesn't matter a lot since the motor and worm gear box are separate from the regulator mechanism. There is a spur gear on the output shaft of the gearmotor which engages the sector gear on the regulator mechanism. It's one of the easiest there is to replace. The more difficult part can be removing the interior door trim without damaging anything. Be patient.